cc  >> Cassie Immel: Thank you  for watching Wednesday Nite  at the Lab tonight.  Tonight we will welcome  Dr. Desai of the Department of  Atmospheric Sciences and Oceanic  Sciences at UW Madison.  He has a BA from the  environmental studies and  computer science at Oberlin  College in Ohio.  He has his masters in geography  with the University of Minnesota  in Minneapolis.  And he got his PhD in  meteorology with the  Pennsylvania State University.  And tonight he's going to be  talking about some surprises  that his lab has found out and  how those recent observations  have begun to challenge some of  our dominate views from the  climate ecosystem and their  relationships.  So now I'd like to welcome  Dr. Desai.  [APPLAUSE]  >> Ankur Desai: Thanks, Cassie,  for a nice introduction.  I hope everyone can hear me  well.  I'm going to talk about  something that is maybe a big  word I first need to define and  something about something you  probably know about which is  climate change at least from  what you know in the media and  maybe what you've learned  elsewhere. 

 And what I want to talk about  are some surprises in  biogeochemistry, and I'll define  that word in a moment, in a  changing climate.  And as Cassie said I'm in the  Atmospheric and Oceanic Sciences  Department here, I'm also  affiliated with the Nelson  Institute on the Environment,  the Center for Climatic Research  where we do a lot of this  research.  So the very first question I  should answer is biogeo what?  Biogeochemistry sounds like a  made up word for the indecisive  scientist.  But it has a specific meaning,  and it relates to the fact that  when we're talking about  ecosystems and we're talking  about how the earth system works  with the atmosphere, there's  both biology, geology and  chemistry and there's even  physics involved.  But we couldn't get all of those  terms to fit together in one  word so we have two words.  So I say land and ocean  ecosystems which I'm going to be  talking about today, primarily  land systems, have biophysical  and biogeochemical dependence on  the atmosphere.  So what I mean by that, by  biophysical I say things that  grow on land or in the ocean  need water, they need heat, they  need solar radiation and so all  of those things, of course, are  provided by the atmosphere so  the exchanges of those  quantities between the two are  going to be our biophysical  interactions.  And then biogeochemical is the  next step.  It's about all the chemical  interactions that occur, the  biochemical interactions.  Photosynthesis is the stuff of  life, as well as respiration  that we do as we're breathing  here digesting our dinner. 

 And it's the cycling of  nutrients, and the ones I want  to focus on here is going to be  carbon but carbon and nitrogen  are probably our two most  important ones especially when  we're thinking about plants.  And what I'll be talking today  is primarily about plants and  plant photosynthesis.  So as the atmosphere is  changing, both changes in CO2  and changes in the climate,  these are changing the  ecosystems.  Ecosystems respond to climate  change and vice versa.  And of course some of these we  can understand, but a lot of  these lead to surprises.  So here's my little  jack-in-the-box.  This one I pulled off a website  of the Consumer Product Safety  Commission, it was recalled.  So that is a surprising  jack-in-the-box.  [LAUGHTER]  But surprises can be pleasant  and pleasing like that,  but sometimes they can be  down right disturbing.  Here's Bill Nye the Science Guy. 

 They can lead to curiosity,  or they can lead  to je ne sais quoi.  This is for the closing  ceremonies at the Vancouver  Winter Olympics where they had  giant inflatable canoes and  beavers and I don't get it.  [LAUGHTER]  Some surprises just leave you  puzzled.  But ecosystems, in general, are  evolutionarily adapted to their  climate.  There's a certain climate and  plants, in general, are going to  adapt to maximize the resources  they can take out of that  climate.  So they're evolutionarily  adapted to the climate in  short-term variability.  So obviously year to year the  weather changes, you have a warm  winter, you have a cold winter,  and most of the small-scale  variability plants are going to  generally survive.  There's going to be some  competitive pressures but not  too much.  So expectations of how these  ecosystems respond to climate  variation by making measurements  of ecosystems, putting them in  the lab, seeing how they change  with temperature, moisture and  light.  It's the bedrock and science  of ecosystem ecology. 

 This is how we study how plants  interact with each other and the  atmosphere that they expect.  But surprises are likely  given that there's a complex  interplay between ecosystems  and climate.  Ecosystems are biologically  active systems that are in  competition for resources with  other systems.  And then the climate, of course,  has variability that may be  beyond what they're adapted to.  But, of course, surprises are no  fun from the perspective of  managing because if we want to  manage an ecosystem, say, to  maximize productivity, say, for  a forest, a surprise, where I'm  defining surprise as an  unexpected response to variation  and climate, is no fun.  But it's also, from my  perspective, it's a lot of fun  because it's how we learn about  how ecosystems respond to  climate.  So it's how science progresses  as well.  And the point, the reason I'm  giving this talk now is I think,  I believe, we are likely to  enter an era where surprises  will become more common.  We're entering an era of climate  destabilization.  So why?  Well, these are maybe not too  surprising figures but it's  always fun it look at them and  just boggle at how much the  world has changed over the last  century. 

 And this is just from 1990.  And I use this slide a lot with  my undergraduates or versions of  this, and that's always amusing  because most of them were born  in like 1989.  So I get to say, since you were  kids, but I don't think I can do  that here with maybe one or two  exceptions.  So since you were younger, since  1990 populations increased 22%  to six and a half billion  people.  Population has doubled since  1975 or since the 1960s,  basically.  Oil consumption grew about 25%.  So we're consuming more oil,  actually at a rate faster than  population is glowing.  85 million barrels,  a barrel is 42 gallons.  85 million of them every day.  22 million of those just in the  US. 

 And gross world product,  how rich we are, grew 40%,  it shrank a little last year.  But $59 trillion.  At the same time, the number of  threatened species, species that  are threatened by habitat  destruction, that may be listed  as endangered but not  necessarily, has increased 40%.  The best estimate is 16,000 but  it's almost certainly a major  underestimate because we  actually don't even know most of  the species on the planet.  So this is kind of the  documented species that we keep  track of, it's actually from  the UN, about 16,000.  And we can see a population  doubling from 1850 to 1930, it  took 80 years to go from  one to two billion.  But from 1930 to 1975, it took  45 years, and the expectation is  in about 2015 we'll be at  eight billion.  There's lots of discussion among  UN population experts about  fertility rates and whether  they'll decline or whether  they'll level off at something  like eight or nine billion.  I'm not an expert in that, I'm  going to go with this and say  there's a lot of change in the  last hundred years.  It's pretty incredible if you  think about it. 

 A lot of it is good things.  Probably the largest causes of  population increases have  primarily been things that have  increased, improved the quality  of life.  We have green revolution which  significantly improved the  amount of agricultural  productivity we can get on a  single hectare of land.  Basically cured malnutrition for  some time until populations  kind of caught up with that.  Public health, vaccination,  hand washing, all of these  things are huge.  Major advances  in the 20th century.  At the same time, though, it's  put a lot of pressure on our  ecosystems and climate.  And one perspective of this is  looking at the amount of carbon  dioxide in the atmosphere.  We'll get to what exactly carbon  dioxide does, but here's a  figure that the National Oceanic  and Atmospheric Administration  makes measurements of CO2 all  around the world including with  partnering with my lab.  And here's a global average  carbon dioxide, and it's  measured in parts per million. 

 So if there's a million  molecules of air then how many  of those are carbon dioxide.  And here we can see from 1980 to  2009, I believe is when this  ends, the blue line is the  monthly average and the red line  is a smooth curve that goes  between them, that interpolates  on the annual scale.  And you can see that we've gone  from something like 340 to 380  parts per million just since  1980.  And you can see since 1990.  Currently we're at something  like 386 parts per million.  Now, at one level that sounds  like a really small number.  But at another level I hope to  convince you that ecosystems  respond strongly to the climate  changes that are interacted with  that change in CO2.  Now I don't necessarily want to  get into a treatise on the  relationship between carbon and  climate, that's a whole topic in  and of itself.  Some of you have heard various  things in the news about it.  We can discuss it and I'm happy  to take questions on it. 

 Here, let's focus on the fact  that we know CO2 is rising.  This is a really solid  measurement.  Here's a picture of one of my  sites.  I have a 400-meter tower in  Northern Wisconsin outside of  Park Falls, and I work with NOAA  to measure CO2 continuously.  We have this little trailer  that's filled with lots of fun  toys.  And right here, for example, is  this system that's measuring  continuously CO2 using infrared  spectroscopy, and then we also  take flask samples where we take  glass tubes and we fill it with  air and we mail it to Boulder,  Colorado, where a lab also  analyzes it for other greenhouse  gases.  They also measure carbon dioxide  and a number of other variables,  and I know how solid these  measurements are.  We measure this down to .2 parts  per million precision.  So we have a really good, solid  feeling for CO2 change in the  atmosphere.  And we know this global average  pretty well. 

 And we have now hundreds of  sites around the world making  this measurement.  And if you go back in time and  we take ice core measurements in  Antarctica and in Greenland and  we look at the bubbles trapped  in ice core.  So here's a picture of an ice  core stolen from Wikipedia,  the font of all sorts of fun  pictures.  And these are annual layers that  you can see in the ice so this  is something like maybe a  century of ice core.  And within each layer you can  date the layer based on  radioisotopes, and you can  extract bubbles of air and  measure the amount of CO2 in the  air, and then you can make a  record of CO2 through time.  And this has been done here,  800,000 years into the past.  So the axis on the bottom is  years before present, and the  axis on the Y axis is carbon  dioxide in parts per million.  And a couple things are really  striking.  So this is a mixture of three  ice cores, and then the  instrumental record is also  tagged on to the end right here.  And the long-term average before  1850 is 232 parts per million. 

 And you can see over 800,000  years we've kind of gone between  something like 180 parts per  million and maybe we've hit  300 parts per million.  Of course the uncertainty on  these measurements are much  larger than .2 PPM because of  all the issues that go with  measuring bubbles in ice that  you dug out of a hole in  Antarctica.  But we can see that the  instrumental record shows a  significant and dramatic rise  since the start of the  Industrial Revolution  up to 385 parts per million.  And we know that CO2 is linked  to climate from our long-term  understanding of how earth's  orbital changes occur and how  carbon dioxide and temperature  are linked which I'll describe  in a minute.  But one thing we know, for  example, is all of these periods  here, CO2 is roughly low, are  well-connected to previous ice  ages.  The last ice age ended 11,000  years ago.  And of course we've been since  then coming out of that ice age.  If you talk to geologists  there's some suggestion that we,  theoretically, should be coming  into an ice age, but most likely  we've prevented that.  What geologists talk about is on  a scale of thousands of years.  I'm talking on a scale of a  hundred years. 

 In a hundred years the long-term  changes like that don't matter.  What matters is how we've  changed the atmosphere  through our activities.  And we know it's our activities  because if you look at this,  this is a best estimate of  global energy production from  1850 onward, and so you have  year on the X and a unit of  "x" joules per year, just think  of it as an amount of energy,  and you can see we're using  nuclear, hydro, gas, oil,  coal and wood.  And you go back to 1850 and our  best estimate is we used mostly  wood as our energy source.  Coal kind of comes in especially  mining of much of the anthracite  in Pennsylvania and then into  other parts of the world and  primarily in England as well.  And you bring in oil as it  struck in the late 19th century  starting in Titusville,  Pennsylvania, and moving onward.  And it's a whole bunch of  carbon.  All of these energy sources  except for nuclear and  hydroelectric emit carbon  dioxide when they're burned.  These are all fuels that are  made from long-term deposition  of dead plants and dead sea  shells and dead animals building  up over tens of millions of  years that we've now mined and  burned.  So what we know is that since  1990, in addition to those  population and production  changes, that CO2 emissions  which pretty much track economic  growth also grew 25% just like  gross product to 27 billion tons  of CO2 per year. 

 And CO2 in the atmosphere grew  10%.  Hmm, well, that's a puzzle.  If I said emissions grew 25%,  shouldn't the atmosphere also  grow 25%?  We see here that CO2 grew 10% to  385 parts per million.  At current rates, we know that  CO2 is likely to exceed  500 parts per million  sometime this century.  And if we go back to this slide,  500 parts per million is not  even on this graph.  We're way, way up there.  So there's bound to be surprises  in how ecosystems respond to the  significant change in CO2 in the  atmosphere, first of all, and  second of all the climate  response to that.  But this puzzle here, why is the  rate of atmospheric CO2 half the  rate of emissions, roughly?  Every year we pump out 27  billion tons, and the atmosphere  only grows about half that much.  Well, here's a figure showing,  in the red curve here, total  fossil fuel emissions from 1950  onward, and this ends about  2000.  And that's a mix of both fossil  fuel emissions and then land use  emissions which is primarily  deforestation primarily in the  tropics leading to a significant  quantity of carbon being added  to the atmosphere. 

 And you look at the red curve  and focus on the red curve  compared to the bar graph.  The bar graph is how much the  atmosphere grew.  And two things become obvious.  One, this curve here is very  smooth, this bar graph is very  messy.  It's not because it's noise,  it's because the atmosphere  really has lots of variability  year to year in how fast it  grows.  And if you look at the  difference between the two,  that's going to be something  related to things that use  carbon and how much they use it.  And so I call it the ecosystem  carbon sink.  If we emit this much carbon and  the atmosphere only grows this  much, then the difference  between the two must have gone  somewhere.  And where it goes is into the  land and into the ocean.  And one thing that's very  interesting about the land and  the ocean is unlike our fossil  fuel emissions which is very  smooth, and this curve we know  pretty well because we pay for  fossil fuels, therefore we keep  track of things like that. 

 Unless you're lucky  and you get them for free.  And the ecosystems respond,  they're very dynamic.  Year to year they take a  different amount of carbon.  What I'm trying to get to here  is that the oceans in general  are nowhere near as dynamic as  the land.  And partly it's because the  oceans have a lot of heat  reservoir, they respond slowly  to changes, there's lots of  mixing and so while oceans are  continually take up carbon year  to year they do some amount.  So we can say we can take out  some of this to oceans.  But really this year to year  variability is strongly driven  by small water bodies and by  land systems.  So we need to understand how  ecosystems take up carbon if  we're going to understand how  atmospheric carbon dioxide grows  which is going to be our primary  driver of climate change.  This is a complex figure so no  need for me to really walk  through this other than to say  we know to some extent the  global scale where carbon goes.  About half of it goes into the  ocean which is all of the boxes  on the right side. 

 And this is kind of a best guess  estimate of all of those  numbers.  And on the right about half of  it goes into the land, into the  vegetation and into the soil,  eventually.  And you can see fossil fuels on  the bottom.  I should be pointing, I should  use this.  Fossil fuels on the bottom, and  this is what we're emitting and  this is where the stuff is going  in, eventually.  The problem is figuring out how  much goes into each one of  these.  And then figuring out how if you  change the climate and if you  change the CO2 how do those  things change.  And that turns out to be an  interesting puzzle.  And the big deal, of course  from the perspective of climate,  is for all debates about climate  aside, the science between  carbon dioxide and how to  radiation budget the amount of  energy that's used by the  atmosphere is very solid.  I can write a climate model in  two equations. 

 This is what I do in my class.  And you can exactly pretty much  track the temperature change in  the 20th century and get a  pretty good estimate of the  temperature change in the  21 century just by making simple  assumptions.  Because what we know is that  carbon dioxide, this is a figure  from the Intergovernmental Panel  on Climate Change for assessment  and reported in 2007, I  encourage everyone to read the  summary for policymakers, very  accessible to the public,  available online PDF.  And one of the figures that's a  classic figurer is this figure  here that shows the amount of  forcing and radiation.  So the amount of energy that's  stored in the atmospheric system  in watts per square meter due to  changes in the earth's  atmosphere from carbon dioxide,  methane, nitrous oxide,  halocarbons, everything else.  So you see up in front I circled  these because these are ones  that land ecosystems respond to.  The amount of CO2 in the  atmosphere is strongly going to  be driven by the fossil fuel  rate on the land and the same  thing with methane.  And then there's these ones on  the bottom.  Because the other way to change  earth's climate is not by  changing the atmospheric  composition but by changing the  surface of the earth.  Clearing land changes the  amount, say, how bright land is  which affects how much energy  goes back into the atmosphere. 

 And you can see here these  numbers here are positive which  means increased CO2 has  generally been a net warming on  the atmosphere.  But land use, and these are  aerosols, so essentially when  plants emit and factories and  fossil fuels emit particles that  make it dimmer so that blocks  the sun out, basically, and then  it also changes how clouds grow.  So those generally, we suspect,  have mostly a cooling effect.  But the net effect total, this  plus this, is still in that  warming effect.  And this is what we know for the  20th century, about one and a  half watts per square meter  leading to roughly a half degree  Celsius or a one degree  Fahrenheit change in global  average temperature.  And this works because we have a  pretty good handle on how energy  flows through the system,  through the atmosphere, through  the ocean and the land.  This is a another classic figure  from Kevin Trenberth.  This is an updated version that  he recently published about the  amount of energy flowing in from  the sun, through the atmosphere,  through the surface, back into  the atmosphere and then back out  to space.  This is also once again a  complex figure that has a lot of  numbers.  We can simplify this by just  putting a bunch of circles on   it, thanks to the magic of  PowerPoint, and we can think of  this as basically sunlight,  infrared radiation that's  emitted by the earth's surface  and interacts with the  atmosphere, weather which kind  of works in between everything,  moves stuff around, weather  moves heat and moisture around,  it brings cold air from Canada  and warm air from Texas up here,  and land and oceans. 

 What's interesting about this  figure, the atmosphere doesn't  do all that much with solar  energy, it reflects some of it,  it absorbs some of it, but most  of it gets absorbed by the  surface.  The surface then heats up and  emits infrared radiation which  is absorbed by greenhouse gases  in the atmosphere, primarily  water vapor and carbon dioxide.  Now I don't mention water vapor  in climate change discussions  but water vapor is a feedback.  It's very hard to control the  amount of water vapor in the  atmosphere because water is the  active gas that's responding  primarily to temperature.  It's by changing to CO2 that  water vapor then changes to  temperature changes that then  lead to feedbacks.  But what we say here is  basically for all of these  pieces, the solar, the infrared  and the weather they're all  connected to the land and ocean  ecosystems.  So feedbacks between how the  land and ocean ecosystems absorb  heat, moisture, carbon and  nutrients, biophysical and  biogeochemical, strongly are  going to impact atmospheric  climate.  And the big deal is this is now  an estimate, once again from the  IPCC, of the last thousand years  of global average temperature.  And this is from a mix of  tree rings, plus ice cores,  plus a few other data sets.  What you can see is obviously  there's a lot of uncertainty to  this as you go further back in  time, and some of you might have  followed some of the debate with  the recent email scandal at the  Climatic Research Unit. 

 A lot of that was about tree  rings and how to derive  temperatures from that.  I'm not an expert in that so I'm  going to go with this and say  roughly we've had, over the last  thousand years, a relatively  stable climate.  So over the period of,  essentially, the flourishing and  progress of human civilization,  we've generally had a stable  climate, and though we have had  climate fluctuations, they're  generally related to large scale  disruptions in human  civilization.  And most of these have generally  been related to things like  volcanic explosions or large  scale climate variability.  Starting around the mid-19th  century we start seeing a  warming effect, some of this is  natural, some of this is related  to fossil fuel combustion, and  into the 20th century.  Now what's interesting is now if  we go to a future of 500 to  maybe a thousand parts per  million of CO2, what do we  expect?  And really it's all about this  figure.  What we do when we do climate  modeling is try to quantify  every single piece of this, and  then try to understand how  changing to CO2 impacts that.  Now what you'll see is this  really large spread.  That large spread is not from  our lack of understanding of how  things work.  That large spread is down here  in this so-called scenario. 

 It's about people, people are  unpredictable.  How many are there going to be  and what kind of energy are they  going to use and where are they  going to emit it?  And so we have to make  assumptions.  We call these scenarios and  there's many scenarios based on  what expect our future to look  like.  And that's what's driving a lot  of this uncertainty of this one  to six degrees Celsius, which is  roughly two to 10 degrees  Fahrenheit, change in  temperature over the next  hundred years.  The climate uncertainty from the  modeling and from our work of  understanding all of those  pieces are mostly in here.  Now I'm going to say some of the  surprises are likely outside of  that envelope.  Now you'll see two other lines  on here.  This red line that says  historical high temperature  level for the last 400,000  years.  I should say over the four and a  half billion year history of the  earth there's been plenty of  temperatures that have been far  above this and certainly ones  that maybe have been lower than  this.  But we're not interested in that  because there were no ecosystems  necessarily back then. 

 We're interested in recent  change.  And you can see here proposed  temperature thresholds for  so-called dangerous climate  change.  And dangerous is maybe a loaded  word.  The point here is most people  agree that ecosystem surprises  and the way ecosystems respond  to climate are likely to be more  dramatic when you get above  about two degrees above where we  are now.  So a lot of negotiation has been  based on how do we keep climate  to warming beyond two degrees  because that's when we believe a  lot of things like agricultural  productivity, which under a  warming climate should increase,  after two degrees it starts to  decrease in most areas of the  world.  Is focused on here in this idea  of how do we stay under that.  It turns out to be a really,  really hard target if we don't  put a lot of investment, say,  into moving away from fossil  fuels.  And we can make projections then  of climate change here from the  decade of 2020 and the decade of  2090, and you can see in 2020, a  mere decade or so away from now,  we would expect at least some  moderate amount of warming maybe  on the order of a degree.  It might be even hard to detect  in lots of parts of the world,  maybe even a few spots that are  are still cooling.  But by 2090, assuming business  as usual in fossil fuel  emissions, we'd expect  significant warming, especially  at high latitudes. 

 Also in the tropics this is here  to like signal in the tropical  Pacific about warmer  El Nino-like state.  Maybe some cooling out here in  Greenland or less warming  related to ice melt coming off  of Greenland and into the  oceans.  Lots and lots of interesting  little pieces to that.  What I'm interested in is can we  use measurements today to  understand how ecosystems  respond to changes in the  temperature to help us improve  our understanding of how these  larger scale climate  uncertainties and climate  changes are going feed back.  And we can see this already in  Wisconsin in terms of climate  change.  This is for 1950 to 2006, a very  careful work by Chris Kucharik  here at UW and a grad student,  working on changes in daily  maximum and minimum temperature.  And climate change, when you get  down to this scale that  ecosystems care about, the  regional scale, so here's a map  of Wisconsin, reds are warming,  blues are cooling, is very  complex at that little scale  because all sorts of little  pieces occur.  As you can see here, changes in  winter maximum and minimum  temperature are the strongest  trend over the last 50 years.  Something like several degrees  Fahrenheit over the last 50  years.  And I think most of us have an  intuitive sense for that. 

 Winters have generally been  warmer, last winter or so as an  expectation to that, but  actually globally it's been one  of the warmest winters.  It's the second warmest January  in a hundred years.  There was, obviously, not so  great winter in Vancouver with  cherry blossoms going on every  where.  Not so great for skiing anyway.  In the summer maximum  temperatures have actually been  cooling in Wisconsin.  So we have all of these  interesting feedbacks that we  need to understand, and fall is  even more puzzling.  But we have a problem which is  that if we try to model how the  land uptake, the amount of  carbon dioxide being taken up by  the land, changes with time and  we take our best models and our  best guesses of how that does,  and we look here from 1850 to  2100 and here's land uptake in  billions of ton of carbon per  year, over the 20th century  all of these models, each on of  these lines is a different  model, they all kind of agree.  But then you start adding  climate change on it, and you  start getting out of the  envelope where these ecosystems  are adapted to and we have lots  and lots of uncertainty about  which direction they'll go in  because of competitive pressure,  because of climate stress,  because of CO2 fertilization so  increasing CO2, feeding the  plants basically.  And some of these models go nuts  in the future.  They start really emitting large  quantities of carbon. 

 The land system is just  basically giving up.  Essentially what you're seeing  is the soil decomposing at rapid  rates, permafrost melting.  Other models are like this is  the most beautiful world I've  ever lived in because we're  going to have a lush tropical  garden.  Which one is right?  I don't know, we don't know.  No surprises here.  What I'm going to tell is what  I'm going do.  The better we can reduce the  uncertainty of how carbon  responds to climate and  ecosystems, the better we can  model future climate change.  That's really our goal here is  to understand climate change in  response to ecosystems.  Now I'm going to present three  stories, with however much time  I have, to illustrate some  surprises that our lab has  worked on that are helping us  understand how to improve and  make this picture better so that  instead of all of this spaghetti  out here, we can have kind of  some sort of understanding  predictability.  Right now we lack a  predictability. 

 And this is going to add a lot  of uncertainty to that  projection of future climate  change.  So my first story.  This one's mostly a biophysical  feedback.  So this is about ecosystems  responding to heat, moisture,  and this one is about heat.  We know roughly that is takes  longer to boil a pot of water  than to heat up a room.  Water takes longer to warm up  than air.  And we know this in a climate  system the oceans have a lagged  response to the atmosphere.  The oceans are receiving heat  from the atmosphere and they  take a long time to heat up.  So climate change warms air  faster than water should seem  like a really straightforward  response.  And here's my little figure of  that if you're a visual thinker. 

 Some amount of forcing, and I  put it in watts per square  meter, change in temperature.  Here's land.  You add forcing, it gets warmer.  Here's water, it should take  less.  So my hypothesis should be that  large lakes, like the Great  Lakes, the ecosystems are  generally buffered from the  impact of global warming.  They shouldn't necessarily be  all that impacted by changes in  temperature.  And here's some big lakes.  This is an air photo of the  Great Lakes, and here we are  down here in the lesser Great  Lake.  And here's Lake Superior.  World's largest lake by surface  area, second or third largest by  volume depending on which seas  you count as lakes. 

 And here we've taken buoy data  from the lake and we've taken  air temperature data from a  number of other stations and  interpolated them over the lake  and we have good measurements  from 1985 to about the present.  And we look at the land  temperature and we can see a  pretty robust warming trend in  land over here.  This is summer average.  And we see a pretty nice trend  in water too.  And, in fact, if you subtract  water minus land, and so this is  delta temperature, that looks  good.  But this trend is decreasing  closer to zero.  What that implies is that water  in Lake Superior in the summer  is warming faster than land.  That's a surprise.  That's how we are in the lab  when we find something exciting,  generally.  Not with the red hair, though. 

 What's going on?  So let's take a look at one  buoy.  So here's a single buoy where  we've made temperature  measurements, my colleague  Jay Austin at University  of Minnesota Duluth  has worked most on this.  And you can see, of course, that  they put the buoy in water in  March after you're out of the  ice free season.  April actually here in northern  Wisconsin.  And it warms very slowly because  the lake is really mixed down.  As you get warmer, warm water is  less dense above four degrees  Celsius.  That water is going to kind of  stratify.  So you're going to have warm  water on top and cold water on  the bottom.  How many people here like to  swim in Lake Superior?  Not many.  It's pretty cold, right?  Maybe a few of you do,  very brave. 

 But it's cold most of the year.  Except for that shallow surface  water, the first tens of meters.  So usually sometime in the  middle of the summer you can  actually get into the water and  it's okay.  But can see as soon as that  water stratifies, and here's  picture here based on some  measurements we made under water  and we've interpolated it using  a model, of temperature with  depth.  So you can see from surface down  to a hundred meters, this isn't  exactly the same location but  it's similar.  And you can see 20 degrees  Celsius to near zero.  And as soon as that lake  stratifies and you have this  warm layer on top of this really  cold layer, the lowest, deepest  depths of Lake Superior stay  cold year round, it starts to  warm rapidly.  And you have storms occasionally  that mix some of that water down  and it gets really cold right  after a water storm,  a storm the water gets cold.  But for the most part it says  very warm.  And then fall comes, storms come  through, it gets really windy,  it mixes everything up again and  that cold water comes near the  surface and ice starts to form  in the winter. 

 Well, it turns out, based on the  research being done here, that  if you look at the amount of ice  on the lake, so the total  amount of fractional coverage,  Lake Superior rarely freezes  over, but the amount of ice  is going to strongly control  when this lake starts to mix  and stratify, which is then  going to affect how much heat  we can get in a surface  part of the lake, where  most of the ecosystems in  the lake are photosynthesizing.  So what we find is that from  1973 to 2005, through the work  of Jay Austin and John Magnuson  who are experts on lake ice,  lake ice coverage,  average coverage is in blue,  or average is about 25%,  has declined significantly.  And it's gone up in the last  year or two, but in the last  year it was a pretty record ice  cover.  And you can see maximum ice  coverage, of course, every once  in a while freezes over, and  minimum ice coverage, of course,  in the winter is just going to  be near zero.  This decline means warmer  winters equals less ice equals  more heat into the lake.  More time to build this  temperature trend into the lake.  Which then means warmer summers.  So warm summer lakes.  And this is the main reason that  this lake is warming faster than  the atmosphere above it in the  summer is because it's a memory  effect of what's going on in the  winter.  Now what's the ecosystem impact  to this?  And that's a little bit more  complicated because lake  ecosystems are not just  dependent on temperature,  they're dependent on exchange  between the atmosphere of carbon  dioxide in the water which have  primarily a chemical reaction. 

 What we see if we actually take  a first order model of Lake  Superior circulation, we couple  it to a model of lakes  ecosystem, and I'm going to  focus not on the top one, we'll  come back to this one with time,  is the length of the stratified  season.  So the number of days in the  stratified, the stratified  season is when ecosystems can  grow because it's warm,  is slowly increasing with time.  And the depth of the mix layer,  so how deep down the layer of  warm water is, has gotten maybe  slightly deeper.  What's the impact of this?  Hard to tell.  What we've done so far is we've  developed this 3-D model,  primarily my colleague in our  department, Galen McKinley  and her grad student, they've  run the 3-D model of lake  circulation and productivity.  And what you see in the blue  line is the model's estimate of  lake productivity in amount of  partial pressure of carbon  dioxide in the water.  And what you see in red is what  the atmosphere has, how much CO2  is in the atmosphere.  And it's the difference between  the two that's going to  determine how much CO2 is going  to come in or out of the lake.  If there's more CO2 in the  water, then the air is going to  come out and vice versa.  Impacts?  We don't know. 

 Our best guess, if we look at  models and we look at the  seasonal cycle of our PCO2, our  partial pressure of carbon  dioxide in the water, CO2 is  dissolved in gas phase in water,  there's a lot of variability and  it seems to be related to that  stratified season length.  So you compare, for example,  1997, a cool year;  1998, an El Nino year, warm.  And you can see there's this  really big difference.  1997 is in red,  1998 is in green.  Check out how different that  cycle of CO2 is in the lake.  We're still at a stage of trying  to figure out how important is  that impact.  Our estimate so far is that it  probably does impact the  productivity of the lake to a  significant quantity, but on a  basin-wide scale the  productivity at that lake is so  low that the variability maybe  isn't significant for the  perspective of ecosystem change.  It is a surprise to the lake.  And of course the other thing  that's happening in the lake  with warmer lakes more  evaporation is dropping lake  levels.  And that, of course, affects  infrastructure on the lake which  has been a big issue up there  for the last several years. 

 So the moral so far of this  story, this is a short story, I  like short stories, large lake  heat budgets are sensitive to  the dynamics of ice and lake  heat budgets drive lake  stratification and,  consequently, lake productivity.  So now I'm going to fix my  little figure here, and if I'm  going to add large lakes and if  I'm going to understand how  ecosystems and climate interact,  I need to be sensitive that  lakes with ice are going to act  differently than my assumption  of how water normally is.  So I can draw this new line.  Let's go to something maybe a  little bit more familiar, which  is a forest.  And maybe we can do better in a  forest than a lake.  Lakes are messy.  They're wet and it's hard to get  measurements in them.  There's very few measurements  actually in Lake Superior  productivity.  So story two.  A warmer spring. 

 In general, we've seen globally  climate-wise, spring has been  warming relatively fast, we saw  that in the Wisconsin slides  too, so if spring warms  then plants can start growing  earlier.  We can put stuff in the ground.  Probably many of you who are  gardeners have this kind of  sense that you can actually get  stuff in the ground earlier than  you used to.  The USDA, a few years ago, just  updated all of their maps so  that we have now moved zones  from the little zone maps they  put on the seeds.  They did that really quietly,  actually, without really making  much publicity about it.  A warmer spring leads to longer  growing seasons for plants.  And we're going to look at high  elevation forests where we know  that they're very temperature  limited.  So I say forest productivity in  the Rocky Mountains should  benefit from global warming.  So here's my little map,  productivity, amount of carbon  taken in, and start a spring  early versus late or long  growing season with an early  spring or short growing with a  late spring.  So if you have a short growing  season, you have low  productivity; if you have a long  growing season you have lots of  productivity. 

 That makes sense.  A lot of these climate models  expect warmer temperatures  leading more productivity in  most forests.  And we know this from  measurements.  Here's some measurements in two  north eastern forests, a  deciduous forest and a spruce  forest in Massachusetts and in  Maine, respectively.  And we know that the onset of  spring, late springs lead to  lower productivity, this is  gross primary production  anomaly, so don't worry about  what that is in detail but its  productivity.  And early springs lead to higher  productivity.  It's a very strong correlation  in this forest.  And this is where we have a lot  of information here at Harvard  Forest.  And we know in high elevations  that spring has been rapidly  warming in many mountain areas  because if you have changes in  temperatures, you're less  buffered from other landscapes  in the mountains.  So this is from work from my  graduate student who's been  looking at temperature trends in  mountainous areas. 

 This is elevation on the bottom,  it's kind of cut off here, sorry  about that, and temperature per  year, degrees per year over the  last 30 years.  And you can see there's a lot of  scatter at low elevations and  you can see it's roughly near  zero, maybe positive.  Once you get to high elevations,  you're almost always certainly  positive.  You're seeing it's getting  warmer in degrees per year.  And this is over the entire  western US.  But here are some measurements  made of productivity.  And this is a different measure,  but it's related, positive is  more uptake, so more positive,  more uptake.  And you can see here growing  season length.  Short.  Long. 

 Short growing seasons, lots of  productivity.  Long growing seasons,  less productivity.  Hmm, that's not right.  That's a surprise.  That's a cute baby.  I don't know who it is.  A little bit on measurement  since I'm a measurement person,  I like to talk about how these  things are measured.  Those measurements made in those  are based on something known as  eddy covariance.  And the idea here is that the  atmosphere is continually  turbulent and if you stick  measurements that measure that  turbulence above a forest and  you look at the CO2 coming up  and down and you measure how  fast it's going up and down by  measuring wind speeds and carbon  dioxide with these two  instruments here and you do this  10 times a second for an entire  year and then you average these  things up at 30 minute intervals  and then you look at annual  values, you can estimate annual  productivity.  It's a lot of work. 

 And you have to build these  towers in the woods, which is  fun to do, and it's a lot of  data coming from essentially  very high tech sensor, but it  turns out to be a really good  way to look at how ecosystems  respond to weather and climate.  So this tower here, the  measurements I showed you are  from sub-alpine spruce  and lodge pole pine dominated  forest.  And here's the tower and here's  the annual measurements.  So this is the average seasonal  cycle over the last decade at  this site.  And you can see here this is  daily uptake.  In the winter it's negative  because basically all that's  happening is respiration so  you're not taking up any carbon,  you're just decomposing.  And then suddenly spring comes  in.  We come right up.  Very, very fast things green up.  Even though this is an evergreen  forest, the productivity still  works like a deciduous forest. 

 It really comes up fast as soon   as the snow melts and as soon as  the temperatures warm.  But then something funny happens  in the summer.  It's starts to ramp down.  And if anyone's been out in the  southwest US, you know that in  late July, early August, things  really start looking brown out  there.  And what's happening is moisture  stress.  It just doesn't rain a lot in  the summer.  Until later in August.  If you go back out there in late  August it seems like there's a  thunderstorm every two days.  And especially up there in the  mountains.  Almost every day there's a  thunderstorm. 

 It's incredible.  We're actually kind of scared to  work on this tower in that time  of the year because you're  always keeping your shoulder out  looking for lightning.  That's why I hire grad students  to go out there instead.  [LAUGHTER]  But you can see  it comes back up.  And then winter comes in and it  shuts down.  So what's happening?  So here's that figure again  about production and growing  season.  It turns out, and this is work  from a grad student  at the University of Colorado,  who showed that if you look at  snow water equivalent, which is  a measure of the amount of  moisture in snow, in late winter  and you compare it to growing  season length, it's really  strongly correlated, almost in  the same exact pattern as NEP,  as production.  And what that implies and what  you can see here in this figure  on the right, is the first day  of the growing season is  directly, linearly correlated  with how much snow is available.  So if you have more snow, it  takes longer to melt and then  even if you have a warm spring,  you're going to have some of  that snow stick around.  So what's going on?  Well, it turns out that snow,  that the forests in the Rocky  Mountains and other sub-alpine  mountainous areas are incredibly  dependent on snow for water. 

 Because they don't get a lot of  rain in the summer, their  productivity is driven almost  entirely by snow.  And so here's a model where  we've taken an ecosystem model  and we've kept track of the  amount of snow and water where  the water is coming from that's  used by a plant.  And we can actually do this by  looking at deuterium isotopes in  snow and water and they have  different signals.  So if you go and take sap out of  a tree and you measure the  amount of deuterium in it, you  can tell whether that water was  from old snow or from fresh  precipitation.  And you can see from this the  amount of productivity driven by  snow is huge.  It's a majority of this forest.  So the amount of snow strongly  drives how productive this  forest is going to be in the  summer.  That's interesting.  We didn't really know that.  So the moral here now is that  warming temperature is not  necessarily a net positive for  productivity. 

 Because changes in moisture in  snow really matter in western  forests.  So while this maybe true in  eastern temperate forests, it's  almost certainly the case that  this is more likely the case for  mountain sub-alpine forests.  And it tells us that we need to  do a better job modeling the  water cycle in our  understandings of carbon cycle.  And that's where a lot of the  science is.  Last story and then some  thoughts.  Wet places like temperate,  let's get away from the Rocky  Mountains where we know  it's really dry all summer.  Let's go somewhere where it's  wet.  Wet places like temperate  regions like here, especially  north here, northern Wisconsin,  are not sensitive to variations  in precipitation.  So year to year it might be a  little bit -- or it might be a  little bit dryer and, yeah, your  garden might respond to it, but  a forest as a whole they have a  lot of mass, biomass, they  should generally be well adapted  to taking advantage of the fact  that there's ample moisture all  summer long.  And especially wetlands. 

 Wetlands are inundated with  water.  North temperate wetlands  shouldn't vary with the  groundwater elevation that's  fluctuating with the amount of  precipitation sending in the  water.  So here's my little plus or  minus 10% precip and  productivity.  Flat line.  Some work here by my graduate  student who's in the audience  now.  Which is good.  Beautiful slides.  A bunch of wetlands that he's  been working at, and so here we  are in northern Wisconsin which  is a wet place and here's the  boreal forest in Canada, also  pretty wet, lots and lots of  wetlands.  The Peatland in Alberta and then  here's another bog in Ontario  and a few sites right here that  our lab maintains and runs.  And here's picture of a few of  those. 

 And these are all, once again,  the same technology, eddy  covariance.  Now we don't need a tall tower  because most of the vegetation  is pretty short.  So we can go and build these  little tripods and platforms,  maybe get a little bit taller,  and get the same kind of  measurement.  continuous, 10 times a second  measurement of exchange between  the atmosphere and the surface  of carbon dioxide, moisture,  heat, momentum and then infer  annual productivity from that.  And if we look at all of these  wetlands, some of them are fens  which means they're primarily  driven by groundwater input and  they're not very acidic so you  have a wider variety of  vegetation on them versus bogs  where you have kind of low  peatlands and kind of more mossy  type vegetation.  And if you look at the fen and  you look at productivity across  that gradient and you look at  each site has multiple years of  data, there's a really strong  relationship between water table  height, which is how high the  water is either below ground or  above ground, and productivity.  And dry conditions lead to  higher productivity in the fens.  Wet conditions lead to low  productivity.  That's weird.  That shouldn't be the case. 

 So once again a surprise.  Now a baby monkey sort of  devolving here.  Water table elevation, so here's  some data from one of our sites  where we measured water table  with a pressure transducer.  You can kind of use atmospheric  pressure to infer fluctuations  in water.  Is driven by precipitation and  evaporation.  That makes sense.  So here is one wetland site, a  shrub wetland, where water table  has been declining continuously  for seven years as this area has  been drying out.  And we know that basically  annual precipitation values are  strongly related to that water  table depth.  So we know that precipitation is  driving this wetland.  Precipitation is affecting water  table is affecting productivity. 

 And for Wisconsin it worked  really nice where a lot of these  wetlands are in an area that  we've seen over the last 50  years a strong drying trend.  Precipitation per year.  Most of Wisconsin like most of  the Midwest is getting wetter.  Which you might expect.  A warmer climate means you have  a faster rates of evaporation  which means you have faster  rates of precipitation.  For reasons that we don't quite  understand, this region of  Wisconsin is getting dryer.  Some of this might be lake  effect, this is Michigan, Upper  Peninsula.  Some of it might be feedbacks  between vegetation.  It's very interesting.  And of course this is messy  because we don't have, it's hard  to get good measurements of  precipitation. 

 But because we have this trend,  we have a natural experiment to  see how an ecosystem responds to  drying.  And we know this is more than  just a trend of a few wetlands.  This is a paper published a  couple years ago showing that if  you look at all the Great Lakes,  Superior, Michigan, St. Clair,  Erie, Ontario, and you  look at all these small little    lakes in northern Wisconsin,  Crystal, Sparkling, and big old  Muskie, they're all dropping and  they're all very coherent at how  quickly they're dropping their  levels.  This is water level in meters  standardized.  So we know there's something  about water going on here that's  more than just simple variations  in precipitation.  But it still doesn't explain  what's going on in, say, Canada  where we don't necessarily have  the same robust drying trend.  What we know is to some extent  this is being driven by fens  being a little bit more plastic.  What that means is the  adaptation of plants to changes  in precipitation is going to be  a function of what that species  can do, what is this range of  variability.  And what we see is that as it  dries out, if we look at the  water use efficiency, so the  amount of water use, molecules  of water per amount of molecules  of carbon taken in, as it gets  dryer it actually goes up in  fens.  So fens are actually defending  against drying water. 

 In fact they're doing a really  good job such that their  productivity actually increases  over what you might expect.  Bogs, not so much.  Maybe going more in a direction  you might expect.  It's actually struggling.  So what we think is that, what  we suspect and we don't have a  strong verification of this is  that bog plants are generally  less well adapted to variations  in precipitation.  Whereas, fens generally can do  pretty well.  In fact, they can actually  increase their productivity as  you have taller vegetation  coming in that's able to  actually thrive.  Obviously imagine if you totally  dry out a wetland, it will  eventually become a forest which  is, on average, more productive  than a wetland.  So to some extent this is not as  surprising as we thought.  But the moral is ecosystems in  wet regions are not immune to  shifts in precipitation like we  kind of suspect when we do lots  of simple estimations of how  precip and productivity respond. 

 Plants adapt to change and the  time scale depends on the kind  of ecosystem.  And so maybe temperate fens are  like this: I don't have time,  but some of my other research  I've done shows that maybe  forests actually respond like  this, maybe what you might  expect.  Although it's kind of surprising  that even a forest up here is  going to respond to a 10% change  in precipitation.  So if we were to review the  morals, we say nothing is  simple.  Which is good.  It's job security for me.  But not so fun for managing  ecosystem.  Rising temperature can add  beneficial and deleterious  effects on ecosystems.  Depends on the season, depends  on lags.  So winter snow melt and spring  temperatures impacting lakes and  forest. 

 We have to think about how  climate change in one season  affects something in the future.  Moisture stress tends to  covariate with precipitation and  temperature, and we're not doing  a good job of really thinking  about how moisture impacts  ecosystems at the scale of  understanding climate change.  We know it at the small scale.  You can go in the lab and you  can dry out a plant and see it  wilt.  And you do all of that and  that's basic science.  But once you get out of the  ecosystem in the field, there's  so many interactions playing at  once we don't necessarily have  as good a feel for how things  should respond.  There are many kinds of stresses  on ecosystems.  It's these interactions where we  find our surprises.  Now to wrap up I'm going to talk  about what about feedbacks.  So everything we talked about so  far is about climate impacting  ecosystems. 

 The other direction also  happens.  If ecosystems change, they also  can then change to climate.  Because if you change how much  carbon you're taking in, you're  affecting the atmospheric CO2  budget.  Maybe that's not as important  than other things.  If you cut down a forest or you  change the reflection and the  amount of energy budget, recall  that first picture about how the  land system and the ocean  systems were connected to the  solar radiation, the infrared  radiation and the weather, it  can influence all of those.  You can change some of those by  changing the reflectivity of the  surface.  If you go from, say, a dark  forest to a snow covered field,  you have a very different amount  of solar radiation that's being  absorbed and a very different  temperature that will respond in  the atmosphere.  And here's a classic figure from  Jon Foley, who's at University  of Minnesota, on vegetative case  and you deforest that and you  would expect many changes in  higher surface temperature, less  evaporation, higher reflection  of sunlight, maybe less humanity  leading to reduced  precipitation.  We have some feel for how these  things work.  And of course for each story,  there's a feedback. 

 So if you go back to the lakes,  when we talked about the lakes  getting warmer faster than the  land, well first we know about  simple feedbacks of the lake,  most of us are familiar with  things like lake effect snow.  Of course people in Milwaukee  have just recently been  bombarded with that six-inch  rapid snow fall in two hours  that caused hundreds of  accidents, and so lake effect is  a major part of our life of the  atmosphere being modified by  warm lakes, evaporating water  and then dumping it over cold  land.  And here's a nice satellite  image of all of these little  streaks of clouds being  generated by the lakes.  And so you can see as the wind  blows from west to east that you  generate lake effect clouds.  And this is beautiful.  But there's other things that  are happening.  So some of the work I've done  recently showed that if you look  at the wind speeds over the  lake, and we know it's getting  warmer, the lake is warming  faster than the land, if you  look at the wind speed, over  land, yeah, there's a slight  increase in wind speed.  And this is probably related to  large scale changes in  atmospheric circulation due to  climate change.  So if you look at the lower  atmosphere, we can take  atmospheric models and instead  of looking at the surface we can  look higher up which is more  driven by large scale  circulation, and we can see that  the increase in wind speeds over  land is related to a lower  atmosphere.  But if you look at the lake, and  we have measurements both from  buoys and from satellite  scatterometry where we actually  kind of track sun glints off of  water as it's being pushed by  the wind off of NASA satellites,  we see that there's a strong  trend in wind speeds over the  lake that's faster than the  trend over land. 

 Almost twice as fast.  And it turns out that this is a  feedback.  So as the lake is warming due to  what we talked about earlier,  less ice equals more heat,  that's actually destabilizing  the atmosphere above the lake  which is causing more momentum  to be mixed down to the lake's  surface which is increasing wind  speeds.  And that goes back to that  figure that we showed earlier  that showed current speeds were  also increasing.  So we're seeing an atmospheric  feedback that's then leading to  increases in current speed which  we don't have a good  understanding at all how it's  impacting the lake.  And we can see here there's a  very tight coupling between that  temperature gradient between  land and water and the wind  speed gradient between over the  lake versus over the land.  Story two is interesting, too.  So we talked about productivity  being impacted by temperature  primarily by snow.  There's a whole other story  about biotic competition going  on in western US that's huge.  What we're seeing in the western  US is most forests generally  have various insects that they  generally defoliate or --  or do something. 

 Insects and plants have long  co-evolved.  And we have outbreaks of insects  even up here.  Things like tent caterpillars  every X number of years and it  causes lots of damage to trees  and so forth.  But for the most part trees  recover and they do their thing.  Occasionally there have been  evasive species that are much  more damaging of course, like  emerald ash borer which is  probably going to wipe out  significant quantity of our ash  trees in Wisconsin in the next  decade.  But beyond that, there's also  climate impacts to this.  So the pine beetles which bore  into pine trees and which lead  to direct mortality by cutting  off their nutrient flow, have  been on the march in lots of the  country and they haven't been  dying off like the way they used  to.  So normally you get a pine  beetle outbreak, trees get  killed, pine beetles die in the  winter because it's cold.  Well it's turning out it's  getting warmer in the winter.  These pine beetles need  temperatures near negative 30 or  so to be killed off. 

 In winters past, you would  expect at least one or two cold  outbreaks at 10,000 feet  elevation that are going to be  that cold.  Not surprising.  We haven't had those now.  So what's happening is the range  of these pine beetles, the  mountain pine beetle in British  Columbia and Colorado, also the  spruce beetle and the pinyon ips  beetle throughout the inner  mountain west, have been  expanding in range.  If anyone's been to Colorado  recently or British Columbia  recently and you're driving  around the forest, it's  incredible how many dead trees  there are.  Virtually most of the ski  resorts in Colorado, I'm a big  downhill skier, and you just  spend your time staring at all  these dead trees.  There's going to be a huge  change in what skiing, skiing is  going to look more like the alps  because there's not going to be  these nice tree runs anymore.  Which is sad for me.  But what we're seeing is an  interaction between climate,  warming climate leading to more  beetles that are sticking around  year after year going after a  larger quantity of trees.  They usually go after healthy  trees because they like the sap  of those. 

 Now they're going after stressed  trees, which are then increasing  the potential for forest fires  because a dead forest burns  easily because there's no  moisture in the trees.  Which can then lead to a carbon  cycle feedback.  This is something that's really  emerging in the last few years.  And it's now become so evident,  especially across Wyoming and  Colorado, there's a few towns in  Wyoming that I was reading about  recently decided to cut down all  the trees in the town because  they wanted to stop the spread  of this.  The public is really attuned to  this and they're really attuned  to the climate impacts of this  throughout the southwest US.  And especially in British  Columbia.  The economy of British Columbia  right now, which is primarily  forestry-driven, is expected to  be devastated.  Very interesting feedbacks.  And we can see this is in our  data.  My lab, in collaboration with  the colleague in the Natural  Center for Atmospheric Research,  measures CO2 in the Rocky  Mountains on the tops of  mountain peaks. 

 Fun work.  So here's one in a valley.  This valley has gone from  something about in 2006, 90%  alive to 2009, 90% dead.  This is a huge valley.  This is near Winter Park,  Colorado, Fraser Valley.  And if we look at the nocturnal  CO2 in the valley, which builds  up at night due to  decomposition, it's actually  been going down.  So what we're seeing is as these  plants dry, and here's a nice  aircraft photo out the wing into  Fraser Valley, and this might be  hard to see the colors here but  these trees are all brown.  This is in early summer.  These are all dead lodge pole  pines.  And what we're seeing is CO2 is  going down which is suggesting  to me that there's less  respiration, autotrophic  respiration, so plants that  respire because they take in  carbon, is actually going down. 

 It's very interesting.  We don't know what the impacts  of this is yet.  This is emerging research.  And finally with the third story  we can look at deforestation.  We don't have large scale  deforestation going on around  here.  So this is work from another one  of my grad students who's  looking at simple models of land  atmosphere feedbacks, and where  he's deforested a small region  of the tropics here in the  Amazon, and you can see this  large scale feedback in  precipitation.  It isn't large, we're talking a  few percent decline in  precipitation immediately after  this deforestation.  But you can imagine as you start  playing with this model you can  really ask some interesting  questions.  How is this relevant to story  three which was about northern  wet areas?  Well, while we're not  deforesting land, we're  definitely changing the  composition of the land.  Most of this area was clear-cut  in the late 1800s, early 1900s,  and most of what we see today is  forest that's growing back. 

 And as we go into an era where  we have lots of forests being  replaced, early aspen being  replaced by later hardwoods,  lots of management decisions  being made about which kinds of  forests are going to thrive and  which are going to have to be  replanted, most of the land  around here is managed.  We're going to have a very  different impact on how much  carbon uptake there's going to  be and what kind of feedbacks  there's going to be.  We don't know at all what kind  of feedbacks are likely.  This is fun to look at and this  is something that we're starting  to look into.  This goes back to this initial  figure that just says the only  thing to get out of this is that  there's lots of feedbacks  between ecosystem, climate,  carbon, moisture, and that we  have a lot of to learn about  these by doing these simple  experiments in the field where  we go out, make measurements,  look at natural climate  variability and try to make some  understanding that can then help  us improve those models so that  our uncertainties decline.  So to conclude, different  ecosystems respond differently  to climate change and  temperature and precip.  So a simple moral here is don't  treat all ecosystems with the  same paint brush.  And complex interactions between  the physical environment and all  biological systems, including  plant/insect relationships,  should not be underestimated.  Virtually none of these carbon  cycle models that we're looking  at future CO2 have anything  about insects involved.  Models to incorporate tests and  verify these interactions will  help us anticipate surprises. 

 And so from an management  perspective, the best we can do  is anticipate.  If I can give you a probability  that a surprise is likely over  some period, we can then do a  better job of managing land for  being resilient.  Ecosystem resilience is kind of  what we're looking at for the  buzz word for sustainable  development.  Itself a buzz word.  Slow, steady rates have changed.  So slow, steady change,  ecosystems are well adapted to  slow change.  You can argue the climate has  always been changing, why should  we care?  Well, slow, steady rates of  change allow us to anticipate  and react to surprises, they  allow ecosystems to anticipate  and react to surprises through  evolutionary mechanisms.  Rapid climate change, the kind  that we're seeing over the next  century, is something that maybe  most ecosystems have not been  adapted to, and certainly we  know that in previous geological  rapid climate changes, to the  extent that we have some records  of such, there has been large  scale changes in ecosystems by  looking at pollens.  And so rapid climate surprises  are likely to exacerbate  ecosystem surprises.  So from a policy perspective,  there is a strong motivation to  slow climate change in terms of  minimizing ecosystem disruption  because we know, based on, I  hope I've convinced you that to  some extent there are many  surprises that come from climate  variability. 

 I'd like to acknowledge my lab.  Here's a picture from last year  of many of the folks who work in  my lab and most of the work  could not be done with out them.  Of course our funding agencies,  the graduate school here,  as well as the National Science  Foundation, National  Oceanographic and Atmospheric  Administration, US Department of  Ag, NASA, Department of Energy.  Dozens of collaborators, as you  might imagine all of this  research involves people like  me, who is a meteorologist,  working with ecologists, working  with hydrologists, working  with all sorts of fun people who  have very different ways of  looking at a problem, and when  we sit down and work together,  that's when we learn.  And, of course, the University  of Wisconsin Alumni Association  for this opportunity to present  at Wednesday Nite at the Lab.  And here's the cutest one.  That's mine.  Thanks.  [APPLAUSE]