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The Climate Crisis: Tracking Change, Predicting Trouble

By century’s end, Arctic will feel like US South

Winter is getting warmer, spring is coming earlier, and plants are enjoying an extended growing season in northern areas. But that is not good news.

In this weeklong series, BU researchers explore the science behind Earth’s environmental changes, and what they mean for our future.

“It’s the initial gold rush,” says Ranga Myneni, a College of Arts & Sciences professor of earth and environment, but what will follow will not be pleasant. As vegetation flourishes, it could draw down the water supply, bringing on drought, insect infestations, and forest fires. What was once green, lush land could become brown and barren.

In an article published in Nature Climate Change on March 10, Myneni and 21 collaborators describe how seasonal temperatures and vegetation north of the U.S.-Canada border have shifted over the past 30 years to what is typically experienced four to seven degrees latitude to the south. Should global warming continue at its current pace, Bruce Anderson, a CAS associate professor of earth and environment, who worked with Myneni on the paper, predicts a further latitudinal shift of as much as 20 degrees south by the end of the century. That means arctic and boreal regions of Canada would look and feel much more like the southern United States.

Ranga Myneni, Professor of Earth and Environment, Boston University BU College of Arts and Sciences, International Panel on Climate Change IPCC, climate change research, phenological effects of climate change, global warming

Ranga Myneni, a CAS professor of earth and environment, recently published an article about temperature and vegetation shift in the northern hemisphere in Nature Climate Change. Photo by Kalman Zabarsky

“We have no precedent for this in all of geological history,” Anderson says. “We’re running an uncontrolled experiment.”

Myneni has been sounding the alarm on rising temperatures and increased vegetation in these regions for decades, but with this article he hopes to push the envelope by framing change in terms of seasonal shifts.

Seasons are determined by two factors: the Earth’s tilt, and the planet’s orbit of the sun. Both change only in small, barely perceptible increments over tens of thousands of years. “This is the natural state of affairs,” Myneni says. But, “if you change the solar radiation distribution on our planet, you can change the climatic character of the seasons—most importantly, the temperature difference between winter and summer.”

So, Myneni asks, are seasons changing because of a shift in solar radiation, or is it something else?

The work of American scientist Charles David Keeling helps answer that question. Every year from 1958 to 2005, Keeling measured the level of carbon dioxide in the atmosphere from points in Hawaii and Alaska. His data showed that levels of the gas have been increasing over time and that they fluctuate in an annual cycle as plants absorb carbon dioxide and release oxygen (or photosynthesize) during the northern hemisphere’s growing season, and reverse modes (or respire) during the dormant season. Keeling noticed that swings in this cycle, now called the Keeling Curve, were getting larger and were most pronounced during photosynthetic periods. More photosynthesis meant more green, leafy vegetation around the globe.

change in vegetation growth per decade in the northern hemisphere, Ranga Myneni, pheonology phenological effects of climate change, global warming climate change research, Boston University Department of Earth and Environment

This aerial view of Earth reveals the change in plant growth in the boreal and arctic regions over the past 30 years. Courtesy of NASA Goddard Space Flight Center Scientific Visualization Studio

Myneni was fascinated by Keeling’s discoveries. As a postdoc at NASA’s Goddard Space Flight Center in the early 1990s, he had access to satellite imagery that mapped the Earth’s “greenness,” or vegetation. On a whim, he cold-called Keeling to see if he could compare a decade of satellite data about greenness with carbon dioxide levels Keeling had been plotting over time. The two data sets overlaid nicely. In 1997, Myneni published his findings in Nature, concluding that plant growth in the northern hemisphere had increased by as much as 10 percent over the previous decade, that the increase was driven by a warmer growing season, and that spring was arriving earlier.

So why the warmer growing season? Myneni doubted it was because a god who’s “pissed off at us flips the Earth and the tilt changes” to alter the seasons. He thought it was because people were pumping more greenhouse gases into the atmosphere.

Like other climate scientists, he thought the rising levels of carbon dioxide and other greenhouse gases like methane were absorbing thermal radiation reflected from the Earth, preventing it from escaping the atmosphere. This causes a greenhouse effect, which scientists believe has led to changes like the rise of ocean temperatures, polar ice cap melt, and more land mass exposed to the sun’s rays. The sum effect is a positive feedback loop that continues to warm the Earth, shifting seasonal temperatures.

Myneni noticed that winter temperatures were increasing faster than summer temperatures, leading to earlier springs and a longer growing season. NASA satellite imagery reflected this shift too, with arctic and boreal regions in North America and Eurasia showing an increase in vegetation over recent decades. Compton Tucker, a senior scientist at the Goddard Space Flight Center and another contributor to the paper, says that one third of the northern landscape—a patch roughly the size of the United States—shows vigorously productive vegetation similar to what’s typical farther south. Collaborating scientists in Russia and northern Norway also confirmed increased shrub growth and a tree line that advanced into the tundra. But while some portions of Eurasia continue to green because of plentiful rainfall, pockets of northern Canada have lost vegetation as species compete for a limited water supply.

Advancing treeline into tundra, Finnmark, Norway, Ranga Myneni, pheonology phenological effects of climate change, global warming climate change research, Boston University Department of Earth and Environment

Tree lines are advancing into the northern tundra, such as in Finnmark, Norway. Photo courtesy of Hans Tommervik

All of this hardly means “the tropics are approaching,” Myneni says. “There’s no way mangoes will grow in the Arctic.” It does mean that global migration patterns, water supplies, and relations among plant and animal species will alter radically—threatening the existence of cold-tolerant plants and animals that depend upon them.

Scott Goetz, a senior scientist and deputy director of the Woods Hole Research Center, who also contributed to the paper, expects the change to alter the summer migration of birds to the Arctic and the winter hibernations of bears. “Any significant alterations to temperature and vegetation seasonality are likely to impact life not only in the north,” he says, “but elsewhere in ways that we do not yet know.”

Anderson points out that as permafrost thaws in the Canadian tundra, greater amounts of organic matter will decompose, releasing additional methane into the atmosphere and adding to the greenhouse effect.

“We’re just trying to stay ahead of the train at this point,” he says. “Where we go from here is entirely within our control.” That’s because the biggest uncertainty is not how our atmosphere will respond to more greenhouse gas concentrations, he says, but how much humans can—or will—control carbon dioxide emissions.

“If there was a positive take-home message, it’s that,” Anderson says. “We actually have more control over where our climate is headed than we think.”

Myneni suggests a first step might be signing his Your Climate Change petition, which asks United Nations Secretary General Ban Ki-moon to “act judiciously and expeditiously to protect the Earth from anthropogenic climate change.” He hopes to gather one billion signatures by Earth Day next year.

As of last week, Myneni already had 8,000 signatures. Just 999,992,000 more to go.

The Climate Crisis

Tomorrow, in part three of our series, the Boston ULTRA-Ex (Urban Long-Term Research Area Exploratory) project tracks the city’s carbon digestion.

23 Comments
Leslie Friday, BU Today, Boston University
Leslie Friday

Leslie Friday can be reached at lfriday@bu.edu; follow her on Twitter at @lesliefriday.

23 Comments on The Climate Crisis: Tracking Change, Predicting Trouble

  • Meme Mine on 03.26.2013 at 6:17 am

    They won’t say a climate change crisis is as real and eventual as a comet hit crisis is.
    Help the planet could be on fire maybe?
    But it WAS fun watching you doomers try so hard and be so determined to believe in your Reefer Madness of climate blame. Your grand kids will have to explain the CO2 death threats you used them like fear mongering neocons.
    27 years of maybe means it won’t be or did you want this misery to have been true?
    *Occupywallstreet does not even mention CO2 in its list of demands because of the bank-funded carbon trading stock markets ruled by corporations and trustworthy politicians.

    • cletus van damme on 03.26.2013 at 12:18 pm

      Im a doom and gloomer. However, I focus on the more important, more immediate threat to this country; the 16+ trillion dollars of debt we have, the trillions in unfunded liabilities, and the trillion dollar college debt bubble formed.

      • Kasia on 04.21.2013 at 10:52 am

        and you think that “producing” extra money and pumping it into the economic system will somehow help to ease the long-term effects of climate change?

  • Steven Lehar on 03.26.2013 at 6:49 am

    “Climate Change” (formerly “Global Warming” is the biggest scam ever foisted on mankind! Fact: The earth in an INTERGLACIAL PERIOD, in a long series of glaciations. Another ice age is due! And THAT is the greatest environmental calamity imaginable, grinding the planet down to bedrock! That is because we are on the COLD FRINGE of the planetary “habitable zone”. Every time it gets colder, things get WORSE! Every time things get warmer, things get BETTER! Its Global COOLING that is the problem, Al Gore, not Global Warming! But you can’t make billions of corrupt $dollars mandating people to buy “carbon credits”. WAKE UP America, this one is really obvious! Stop being scammed by people who want to raise your taxes and shut down the economy over a complete and total fiction!

    • EKorman on 03.26.2013 at 8:49 am

      As a student studying the environment and earth science, I can tell you that this is not fiction. If you look at climate records over the past several thousand years, you can see that the Earth goes through natural tectonic and orbital cycles that impact Earth’s climate. However, Earth’s greenhouse gas concentration has shot up exponentially SINCE 1850 (the beginning of the industrial revolution).

      People forget about the fact that there is a time lag between actually putting greenhouse gases into the environment, and then its effects on the environment. So it may look “nice” now, but as temperatures rise, there will be serious droughts, agricultural reproduction, major loses in biodiversity, etc.

      Scientists agree over the actual science–climate change IS occurring. The people that don’t “agree” with this are the POLITICIANS creating the actual policy. The majority of these politicians are probably not scientists.

      • Dan on 03.26.2013 at 10:26 am

        How can you look at climate records for the past several thousand years when people have only been recording climate records for the past 100 years?

        • Chris on 03.26.2013 at 10:46 am

          Geologic evidence.

          • Dan on 03.26.2013 at 11:18 am

            Geologic evidence for record keeping? Geologic evidence cannot account for annual temperature changes by degrees. To read our limited data back into millennia is science by anachronism.

            I am not discounting geologic evidence on the macro. But to pretend we have been measuring what we have not been measuring and lumping two different things together is sloppy or dishonest. I will assume sloppy in good faith.

        • EKorman on 03.26.2013 at 11:07 am

          There are a lot of geologic records you can look at to study climate over the past several thousand (and even million) years. Ice cores go back around 800,000 years; tree rings go back further; sediment cores even more so. But ice cores are really interesting in that they capture air bubbles, which contain CO2. You can actually go back and measure the CO2 concentration in these ice cores, which gives us the climate record that supports climate change studies.

    • Chris on 03.26.2013 at 8:55 am

      The paranoia capitalists have over the second most enthusiastically pro capitalist party never ceases to amaze me. The occurrence of climate change is only controversial to people who are worried more about the monetary costs to business of preventing massive pollution, not among scientists. Even if we make businessmen pay for the damage they cause the environment, they shouldn’t complain, as we appropriate land for them, have gone to war to protect their claims to property in other lands, and ensure workers and their children starve rather than cut into their profits.

      Capitalists should be on bended knee, thanking us for repeatedly getting them out of their own messes, but, like petulant children, instead they whine whenever asked to show the slightest responsibility.

    • tomandsarah on 03.26.2013 at 9:25 am

      could you please point to the specific errors in the IPCC report and the vast climate literature and identify , again specifically , A. where the error is and B. how the research that you have done demonstrates these errors? Once you have done so I suggest you submit your work to Science or Nature as you would be the first person to empirically demonstrate that global warming is a “hoax” .

      Secondly how does one claim global cooling while all the empirical evidence shows your assertion to be incorrect. I think it is you who needs to WAKE UP and accept that you make an argument with no empirical basis. While at the same time questioning the integrity of scientists like Myneni who through their publications make their methods and data available for scrutiny.

      Better yet meet with the faculty quoted in this article and show them where their methods or data are flawed. IF you are so convinced their is a hoax going on put your money where your mouth is and do some of your own work to demonstrate it. Put up, or shut up.

  • Colby Smith on 03.26.2013 at 9:47 am

    You’re right Steve, we SHOULD be in a state of cooling that would lead to an another ice age. But that is a gradual transition, which would give us plenty of time, on the order of 1000s of years, to adapt. Currently however, we have interrupted this natural cooling, and caused one of the steepest increases in global temperature on record. We are on track to see serious and catastrophic conditions in our lifetime. We need to stop fooling around and making a chemistry project out of our atmosphere, and start making the health of our environment a top priority.

    Here are some articles to help you take off your tin foil hat.
    http://www.technologyreview.com/article/416786/global-warming-vs-the-next-ice-age/
    http://news.nationalgeographic.com/news/2009/09/090903-arctic-warming-ice-age.html

  • Paul Daly on 03.26.2013 at 9:52 am

    The next time you attend a climate change event, ask yourself why all the marxists and communists are in attendance.

    Weird, huh?

    Why is it that Putin’s Russia is pushing so hard (as did Chavez before his death) for Climate Change solutions? Does Putin care one iota about the environment? Um, no. But he does see the environmental movement as a way to further his agenda . i.e. Carbon Taxes, Energy Regulation, Stronger Centralized Government.

    Here’s a quiz. Does the political left thrive on:

    A.) Higher taxes and more government
    B.) Lower taxes and limited government.

    The correct answer, of course, would be A.

    And what do the comprehensive climate change solutions generally entail? Naturally, higher taxes and more government control.

    Odd how that works, huh?

    Do the math. Follow the money. The most influential climate change leaders are making millions (or billions in Al Gore’s case), while demanding that you pay more in taxes and cede more freedom and liberty to the government – all in the name of junk science.

    • Colby Smith on 03.26.2013 at 10:38 am

      Please elaborate on whether paying lower taxes is worth having an unlivable climate, how the top scientists from around the world are performing “junk science”, and how money is a higher priority than the health of your environment and yourself.

    • Chris on 03.26.2013 at 10:43 am

      Science declared junk by capitalists… seems legit. When has business ever harmed the environment or worked counter to the interests of people in general? Surely, what we need is stronger business.

  • Alivia on 03.26.2013 at 10:12 am

    Another way students (and everyone) can get involved is by looking to what students (and others) in the Divestment movement are doing!

    HERE is the BU Divest group… message it for details or how to get involved!
    https://www.facebook.com/DivestBU?ref=stream

    And Here is the overarching Divestment movement happening across the US, initiated by 350.org
    http://math.350.org/

  • Ranga Myneni on 03.26.2013 at 12:27 pm

    Sustainable economic growth and actions to curb infusions of greenhouse gases in to the atmosphere are not necessarily mutually exclusive. Collectively, we have to tap our creativity to solve this problem. The science, irrespective of what few deniers say, is pretty much clear. It is time to act judiciously and expeditiously by the policy makers of the world. They will not do it until the people ask for it. Therefore, I initiated a petition – please go to https://www.yourclimatechange.org/ – read/sign the petition and get your family, relatives, friends, colleagues, acquaintances and other contacts to do the same. Change comes bottom-up, not top-down.

  • Andrew Wolfe on 03.26.2013 at 5:37 pm

    If we’re running an “uncontrolled experiment,” then Myneni doesn’t actually know that thirty years of “warming” aren’t random.

    • Undeniable on 03.26.2013 at 6:07 pm

      Really grasping at strings, taking textual bits far out of context there Andrew. Myneni, and Over 97% of climate scientists agree that the “warming” is happening and that it is human-induced, and they have proven it. Read more on that here: http://clmtr.lt/cb/qom0WZ

  • Alfred Wegner on 03.27.2013 at 7:06 pm

    Ok guys, here is how academia works. I know it is complicated, I know that in here you have all those geeks you had hated in your class. But admit it, those geeks, howsoever awkward they might have been, they could have run an intellectual marathon by the time you were taking out your scrapbook. So please first understand why people with IQs much higher than you care to count are scared. And please understand the business they are in.

    1) Peer-review is a process where geeks evaluate geeks. And, remember, geeks never used to take sides. They were kinda adamant about those trivial minutiae and would somehow keep working on them till they were convinced. Peer review, although not all by geeks, is kind of similar. We scientists are an argumentative lot. We analyze everything by what we think to be right. Now answer me this. If most of the smartest people on this planet agree on something in peer-reviewed journals, then what are the chances that you could prove them wrong? Well, not on an anonymous message board, but more like in an international conference, where you have to actually talk for half an hour minutes in front of an audience with an average iq of 140?

    2) OK. Second. For a moment consider this. Take the remote control and switch of the television. How long did it take for your action to reap benefits, i.e., how long did it take to switch of the TV? Instantaneous, right? Have you witnessed an ugly divorce that started of with small misunderstandings and ended with a divorce 5-10 years down the line. OK how long did it take for the divorce to materialize? Would you have guessed from the first small misunderstanding that your lovely wife and you would be divorced 10 years down the line. That was an example of something that takes a long time to develop. What is the similarity between these two events? Nothing. Because they are fundamentally different systems and they react on different timescales. Our earth is another system, which reacts over hundreds, thousands and million year time scales. The technical term for this is ‘deep time’. The longer the time it takes for a system to react the more non-intuitive the system becomes. And that is why you don’t realize that your actions could have severe consequences for the future. Climate change is not like the TV. A cow belches and you expect summer to arrive a day earlier. It is slightly more complicated.

    3) Third. And final. Don’t be too harsh on yourself. Earth science is very strange. Even the brightest tend to ignore the evidence – the physicists however have a certain knack of not quite getting it. Remember that guy called Einstein. Ok, now look up plate tectonics. Einstein opposed plate tectonics till the very end. So don’t worry, imo, it is too late anyway. As James Lovelock would take a sip from a glass of wine and say ‘Lets not worry too much about this thing, only one in seven will live to know how wrong they were few decades back’

  • Ranga Myneni on 03.28.2013 at 8:55 am

    Alfred, I really enjoyed your comment. When I am frustrated arguing with the uninformed or the illogical ones, I would say “Deadenders” and leave, or say “Never argue with a fool – they will drag you down to their level, then beat you with experience” – but now, I will use your response. Again, Thank You!

  • Alfred Wegner on 03.29.2013 at 7:56 am

    You are welcome, Ranga. Good luck with your initiative.

  • Fred on 06.09.2013 at 9:59 am

    Shut down all the power stations, stop using fossil fuel vehicles boats and planes then watch the anarchy unfold hopefully these idiots who propogate this crap will be the first to go. Unfortunatly the enviroment will be the first to go as everybody cuts down trees and kills all the animals to survive.My mother always told me to eat my greens now eating our greens takes on a whole new meaning.

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