Satellite Data Show Plant Growth is Declining on Earth


One idea about climate change suggested that higher temperatures would boost plant growth and food production. That may have been a trend for awhile, where plant growth flourished with a longer growing season, but the latest analysis of satellite data shows that rising global temperatures has reached a tipping point where instead of being beneficial, higher temperatures are causing drought, which is now decreasing plant growth on a planetary scale. This could impact food security, biofuels, and the global carbon cycle. “This is a pretty serious warning that warmer temperatures are not going to endlessly improve plant growth,” said Steven Running from the University of Montana.

During the 1980s and 1990s global terrestrial plant productivity increased as much as six percent. Scientists say that happened because during that time, temperature, solar radiation and water availability — influenced by climate change — were favorable for growth.

During the past ten years, the decline in global plant growth is slight – just one percent. But it may signify a trend.

Interannual shifts in plant productivity (green line) fluctuated in step with shifts in atmospheric carbon dioxide (red line) between 2000 through 2009. Credit: Maosheng Zhao and Steven Running

“These results are extraordinarily significant because they show that the global net effect of climatic warming on the productivity of terrestrial vegetation need not be positive — as was documented for the 1980’s and 1990’s,” said Diane Wickland, of NASA Headquarters and manager of NASA’s Terrestrial Ecology research program.

A 2003 paper in Science led by then University of Montana scientist Ramakrishna Nemani (now at NASA Ames Research Center, Moffett Field, Calif.) showed that land plant productivity was on the rise.
Running and co-author Maosheng Zhao originally set out to update Nemani’s analysis, expecing to see similar results as global average temperatures have continued to climb. Instead, they found that the impact of regional drought overwhelmed the positive influence of a longer growing season, driving down global plant productivity between 2000 and 2009.

The discovery comes from an analysis of plant productivity data from the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite, combined with growing season climate variables including temperature, solar radiation and water. The plant and climate data are factored into an algorithm that describes constraints on plant growth at different geographical locations.

For example, growth is generally limited in high latitudes by temperature and in deserts by water. But regional limitations can vary in their degree of impact on growth throughout the growing season.

Zhao and Running’s analysis showed that since 2000, high-latitude northern hemisphere ecosystems have continued to benefit from warmer temperatures and a longer growing season. But that effect was offset by warming-associated drought that limited growth in the southern hemisphere, resulting in a net global loss of land productivity.

“This past decade’s net decline in terrestrial productivity illustrates that a complex interplay between temperature, rainfall, cloudiness, and carbon dioxide, probably in combination with other factors such as nutrients and land management, will determine future patterns and trends in productivity,” Wickland said.
The researchers plan on maintaining a record of the trends into the future. For one reason, plants act as a carbon dioxide “sink,” and shifting plant productivity is linked to shifting levels of the greenhouse gas in the atmosphere. Also, stresses on plant growth could challenge food production.

“The potential that future warming would cause additional declines does not bode well for the ability of the biosphere to support multiple societal demands for agricultural production, fiber needs, and increasingly, biofuel production,” Zhao said.

“Even if the declining trend of the past decade does not continue, managing forests and croplands for multiple benefits to include food production, biofuel harvest, and carbon storage may become exceedingly challenging in light of the possible impacts of such decadal-scale changes,” Wickland said.

The team published their findings Aug. 20 in Science.

Source: NASA

22 Replies to “Satellite Data Show Plant Growth is Declining on Earth”

  1. A neighbor up the street and I recently spent several hours hauling firewood to his house for splitting (4 cords of dead/dying Tan Oak – caused by ‘Sudden Oak Death Syndrome’ , which has become rampant here in No. Calif. – UGH!). We had a lot of time to chat while driving back forth to pick up the wood. I mentioned your recent article about that giant glacier calving off the ice flow in Greenland and mentioned Global Warming. Opps… mistake! The neighbor, a ‘biker-type’ who has fallen on his head several times, not so patiently explained to me that “YOU can’t say that global warming is caused by man! This isn’t the first time the climate has changed and won’t be the last.” I countered with, “Well this IS the first time there’s been over 6 billion people on Earth burning fires, driving automobiles and otherwise consuming resources – surely that has an effect on our thin atmosphere?”

    Well… he ended up insisting that whatever the cause, “Mankind has every right to use up all the resources on the Earth, cuz “It’s in the Bible”… which left me feeling kind of ill. The good news is, he doesn’t believe in astrology…. And “No”, I told him, I wasn’t interested in joining the “Tea Party” movement.

  2. Might some of the change on the map be produced by differences in agriculture activities? For example, the plant decrease in southern Brazil may reflect clearing of extensive rain forests, whereas increased plant growth in the southeastern US reflects a change from small farming, which involves plowing, to more grassland and timber.

  3. @AQUA

    About your neighbour.
    For most christians the “Mankind has every right to use up all the resources on the Earth, cuz “It’s in the Bible” attitude stems from the words of Genesis 1:26, which states, among other things: “And God said, Let us make man in our image, after our likeness: and let them have dominion over the fish of the sea, and over the fowl of the air, and over the cattle, and over all the earth, and over every creeping thing that creepeth upon the earth.”
    However, next time you talk to him, remind him what Genesis 2:15 has to say on the matter: “And the LORD God took the man, and put him into the garden of Eden to dress it and to keep it.”

    In otherwords, according to the Christian bible, the christian god not only gave us the right to do as we please with the earth, and use it as we see fit, he also gave us the responsibility to look after it and care for it – the corrollary being that the only way these two statements can avoid contradicting each other is if the bible is telling us to use Earth’s resources in a sustainable manner.

    I’ve used this argument several times, and each time it’s been met with stunned silence and (apparent) deep thought.

    Good luck. 🙂

  4. I find it interesting that much of Sub Saharan Africa shows significant plant life productivity, while most of the US, except the Southeast, shows decreased productivity, including the once robustly forested Pacific Northwest. The doubters can spew all the nonsense they like, but the evidence is beginning to overwhelm their arguments.

  5. Hello Aqua,
    I’m no Ned Flanders but you could suggest your friend looks into how much his bible talks up respecting the environment and abhors waste (a form of the sin of gluttony)…
    Leviticus 25:23-24 “…provide for the redemption of the land”.
    Isaiah 24:4-6 “…a curse consumes the earth; its people must bear their guilt”.
    Jeremiah 2:7 “…you came and defiled my land and made my inheritance detestable”.
    Failing that, it’s possible (though somewhat impolite) to spring a trap and remind him of the books combustible properties for when the fire wood runs out. Thus whence the logically challenged doth speaketh forth, lest thou shalt findith an abundance of entertainment value.

  6. Whether you believe in God or not, we do need to own up to our responsibility and take care of this planet.

    The passages referenced are good ones. However, *never* make fun of someone’s religion when trying to make a point. If you offend them, then they may shut you out altogether. Remember, education is the goal.

    I believe that the Earth is warming partly naturally, but our greenhouse gas emissions and widspread deforestation are contributing and escalating the warming trend.

    I’m not sure if this study is taking into account the deforestation thats going on around the globe, especially in the tropics, but I belive that is a major cause of GW. if there are less trees and vegetation to remove CO2 from the air, then there will be more CO2 in the air, even without all of the additional amounts that come from industry. Not to mention all of the decaying wood and plant mater, which is also releasing CO2. It seems like we are just screwing ourselves from every possible angle.

  7. reading this story brought to mind a quote from jim morrison, i believe it went something to the effect,”i’m gonna have my kicks before the whole shithouse goes up in flames”

  8. I agree with Dark Gnat in saying Whether you believe in God or not, we do need to own up to our responsibility and take care of this planet.

    Whatever anyone’s beliefs are and whatever anyone’s standpoint is on GW, AGW and climate change in general, everyone should treat there environment with respect.

  9. OK which izzit? On the one hand we’re told that global warming is causing a wetter climate and we should anticipate floods and storms. Now we’re informed that draughts will be forthcoming. As a chemist, it’s hard for me to accept that changes in a few parts per million CO2 can possibly affect world climate. This flip-flopping and poor science makes human global warming a farce, a conclusion I drew long ago. I’m no Christian. The Earth’s been warming for the last 12,000 years. As a scientist, I dispise the human global warming movement because of their myopic vision, poor data, and downright awful science.

  10. neoguru as a scientist you should know that the term GLOBAL means global and not local.

    Some countries will have wetter climate some countries will have draughts. Many countries will have more draughts followed by more floods and storms.

    Between 1960=315 ppmv, 2010=385ppmv, if my calculation is correct over 50 years the ppmv count increased with 18%

    As a chemist do you really claim that adding 18% more a tiny amount chemical in a solution will have no effect to your complete solution?

    Yes 310 ppmv seems small but if it has no effect then why the hell would you even put the solution in it? Just leave it out.

  11. it is interesting to see people acting like the ostrich… the universe, and we are part of it;-) only exists because of a balance of all forces.

    If you are a believer read the bible (Genesis), if not use common sense and apply logic.

    Our planet is a micro-cosmos of which we are the part disturbing this very delicate balance. Have you ever heard of the Chaos Theory? Every minute detail ultimately influences the whole. As a species we have only occupied a small portion of time on this blue marble and I am absolutely sure nature will do just fine without us.

    As Albert Einstein said: The difference between Intelligence and Stupidity is, that intelligence has its limits…

  12. Not difficult to predict gloabl warming when the planet is at the end of the interglacial period.
    Based on the recorded pattern of glacial-interglacial climate periods, there is an expectation that the naturally occuring global warming should reached approximately +12C temperature difference (increase) from the end of the last glacial cycle. In fact in the last few centuries we have briefly exceeded this +12C difference, but then the global temperature took a +2C dip. We are currently hovering around +10.65C difference as of June, 2010.

    Since we have yet to exceed this glacial-interglacial benchmark of +12C difference, then how can this be attributed to anything but naturally occuring climate change events ? How can AGW take credit for something that would and is happening now anyway? The current data is not even close to suggesting anything other than the glacial-interglacial cycles as the primary driver (influence) to the existing global warming condition the Earth is currently in.

    To understand the timeline a little better, I have referenced an objective study of the current AGW model which also hinges on the CO2 concentrations for their results –
    “The results of the overall trend on climate change at global scale were similar to the estimations so far obtained. The global-mean temperature during the period of 2071 to 2100 increased by 3.0°C in Scenario B1 and 4.0°C in A1B compared to that of 1971 to 2000. Similarly, the precipitation increased by 5.2% in B1 and 6.4% in A1B (Note 1). In the geographic distribution, temperature rise is larger at high latitudes in the Northern Hemisphere and it is larger on land than on sea.”

    Note 1: There are many uncertainties about prediction on the absolute value of temperature rise. Considering all the results from the present models in the world together, it is said that if the concentration of carbon dioxide in the atmosphere is fixed to twice the present value, the temperature rise will range between 1.5 and 4.5°C. In this model, the temperature increased by 4.2°C.

    Note 2: Since year-to-year natural fluctuations are quite large, the number of very hot days in summer and torrential rains won’t always increase monotonously from year to year. In connection with this, generally it is difficult to link the unusual weather on a certain year (this year, for example) with global warming.

    So based on the projections of this study, it would appear the expected increase of the average land-ocean global temperatures to exceed the maximum of +12C from the last glacial period is roughly between the years 2030 and 2060. While previous ice core records indicate that a sustained global temperature of greater than +12C coincides with the appearance of the global cooling cycle, the AGW model projections continue to prognosticate increasing temperature events anywhere from +3.0C to +4.0C by the 22nd century.

    But until global warming exceeds this glacial-interglacial benchmark of +12C difference, then the is no real evidence that the AGW model projection of doom is even viable. I’m guessing we’ll have plenty of global indicators by the year 2025 to prove my point.

  13. …and “a trend for awhile” should be a while. ‘Awhile’ means ‘for a time’, so the article reads “a trend for for a time”

    Dictionary: Awhile, an adverb, is never preceded by a preposition such as for…

  14. Ahemm…. as I mentioned in the post above, MUCH of Northern California is experiencing a MAJOR tree die off! Granted these trees are mostly related to the Oak and sub species thereof – Tan Oak, Live Oak, Coast Oak etc… we’re still talking about BILLIONS of trees which is NO trifling sum and has become a MAJOR fire danger to many parts of the state! Whole mountains of dead or dying trees are just primed to burn with a simple spark – a lightning strike to set off a conflagration?

    Whatever the cause of this phenomena… it doesn’t look good and represents a MAJOR change in California’s forests!

    THEN, take a look at the dying forests of the sub arctic up north, where huge tracts of trees are being killed by beetle invasion from insects normally killed by cold winter temperatures, which is apparently is no longer a factor.,0,539661.story

    The truth about global warming is irrefutable… ANYBODY who refuses to believe the data has obviously spent too little time looking at the facts. Or they are simply ignoring them for political or financial (Greed!) considerations…

  15. For a moment let us put aside whose theory bests fits the data etc.
    I should be able to say everyone agrees its hotter now than 15,000 years ago.

    Is there any way that we can use this to our benefit?
    I know in some ways we already are and already have, but all we seem to do about this is moan and groan and debate who is right and who is wrong.

    Is there something more positive we can do?, besides reminding ourselves to respect the environment as constantly telling people this fact may lead them to rebel against respecting the environment.

  16. @ Spoodle58 “…put aside the data…” Umm.. that’s obviously what’s been and is being done. The economic engines that exist on our tiny planet are the driving force behind MOST of the continuing environmental degradation – that and overpopulation. It appears that only when the forces of negative economic margins occur do the ‘greedy’ attempt any change. Sadly, this may become our only hope?

    Addendum – concerning greed. Those who are motivated by this factor are generally speaking, not concerned about the future. They are too busy accumulating personal wealth which they view as ‘power’. Short term profit is their mantra. Live for today the motto. This appears to be a function of ego which removes concern for others. Philanthropy after all, is an antitheses to greed.

    Hope – there’s always that! I like Ken Kessey’s approach. IF we can create a way to placate the greedy with some sort profit scenario or scheme (Read: prank) that allows them ego gratification and ALSO benefits mankind… then we will have succeeded.

  17. This is a global issue that need to take serious consideration and into an action, we all know the importance of green plants in Earth, I’m proud of my country (Malaysia) still overall has a large green area in this map.

  18. This is rather troublesome. I will say I am not sure how this trend is clearly decoupled from other environment impacts.


  19. @NEOGURU:

    As an alleged chemist, you of all people should know better.

    I suggests you dust off those first year textbooks, brush up on the Beer-Lambert law, take a quick squiz through the NIR spectroscopy sections, and consider how those might apply to this discussion.

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