From NASA:
download large image (700 KB, JPEG) acquired January 1, 2000 – December 31, 2009
download large Hemispheric Trends image (81 KB, PDF)
Conventional wisdom holds that plants should thrive when temperatures warm and the growing season lengthens under a changing climate. A 2003 study showed that plant growth indeed increased as temperatures warmed between 1982 and 1999. But when researchers at the University of Montana updated the study for the last decade, 2000–2009, they discovered that even though the decade was the warmest since instrumental recordkeeping began, plant growth slowed.
The study is significant because plants soak up carbon from the atmosphere as they grow. As growth slows, the amount of carbon plants take up slows as well, leaving more carbon in the atmosphere to contribute to climate change. It is also a warning that a warming climate could bring a decrease in food and biofuel production.
Researchers Maozheng Zhou and Steven Running published the work in Science on August 20, 2010. They used data from the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite to monitor plant growth and calculate the total amount of carbon plants store as they grow, a value called net primary productivity. Their results are illustrated in this image, which shows the change in the amount of carbon consumed by plants between 2000 and 2009. Green areas show where plants grew more (and consumed more carbon), and brown areas show where they grew less. The deeper the color, the stronger the trend.
In general plant growth and consequently the amount of carbon plants store increased in the Northern Hemisphere and decreased in the Southern Hemisphere. The difference, say Zhou and Running, is water. Three things limit plant growth: light, water, and temperature. In the Northern Hemisphere, warmer temperatures and a longer growing season allowed plants to grow more. But in the Southern Hemisphere, drought dominated the decade. Higher temperatures dried plants and soil, generally slowing growth. The attached graphs illustrate the direct relationship between drought and the amount of carbon plants absorbed between 2000 and 2009.
During the decade, large-scale droughts, primarily in the Southern Hemisphere, were strong enough to overwhelm increased plant growth in other places, resulting in decreased plant growth overall. While 65 percent of the Northern Hemisphere’s vegetated land had increasing growth, 70 percent of the Southern Hemisphere’s vegetated land had decreasing growth. Added together, global plant growth decreased slightly in the decade, reducing carbon uptake by an estimated 0.55 petagrams, a one percent decrease.
It is too early to tell if the recent decade marks the beginning of a longer term trend in plant growth related to long-term climate change. Climate is defined by patterns seen over longer periods of time, at least 20-30 years. In the previous 20 years (1982–1999), plant growth and the related carbon uptake increased as much as six percent. Regardless, the observed decrease in plant growth between 2000 and 2009 helps researchers better understand how plants might respond to a changing climate.
“We see this as a bit of a surprise, and potentially significant on a policy level because previous interpretations suggested that global warming might actually help plant growth around the world,” Running said. “This is a pretty serious warning that warmer temperatures are not going to endlessly improve plant growth.”
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A longer NASA feature article and videos describe the results in greater detail. (below)
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From NASA
Drought Drives Decade-Long Decline in Plant Growth
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A snapshot of Earth’s plant productivity in 2003 shows regions of increased productivity (green) and decreased productivity (red). Tracking productivity between 2000 and 2009, researchers found a global net decrease due to regional drought. Credit: NASA Goddard Space Flight Center Scientific Visualization Studio
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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 Earth has done an ecological about-face: Global plant productivity that once flourished under warming temperatures and a lengthened growing season is now on the decline, struck by the stress of drought.
NASA-funded researchers Maosheng Zhao and Steven Running, of the University of Montana in Missoula, discovered the global shift during an analysis of NASA satellite data. Compared with a six-percent increase spanning two earlier decades, the recent ten-year decline is slight — just one percent. The shift, however, could impact food security, biofuels, and the global carbon cycle.
“We see this as a bit of a surprise, and potentially significant on a policy level because previous interpretations suggested that global warming might actually help plant growth around the world,” Running said.
“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.
Conventional wisdom based on previous research held that land plant productivity was on the rise. 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 global terrestrial plant productivity increased as much as six percent between 1982 and 1999. That’s because for nearly two decades, temperature, solar radiation and water availability — influenced by climate change — were favorable for growth.
Setting out to update that analysis, Zhao and Running expected 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 team published their findings Aug. 20 in Science.
“This is a pretty serious warning that warmer temperatures are not going to endlessly improve plant growth,” Running said.
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 very 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.
Related Links: > Related video
This narrated video gives an overview of net primary production and the carbon cycle. High-resolution data from the Moderate Resolution Imaging Spectroradiometer, or MODIS, indicate a net decrease in NPP from 2000-2009, as compared to the previous two decades. Credit: NASA/Michelle Williams
Researchers are keen 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.
“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.”
The only association is in the malfunctioning minds of propagandists. Cold and Dry OR Warm and Wet. Like I said before watch for the focus to now be on drought and not temperature. During Cooling-Drying the narrative will be about the drying, and during Warming-Dampening, the narrative will be about the warmth. Head I win, Tails you loose!
@Dave Springer
‘So having no snow on the ground isn’t vitally important to plant growth?’
Actually no. Having snow on the ground during winter is vitally important if you want your damn crop to survive, because the snow isolates from the deep freeze that can freeze the ground down to six feet and that’ll kill the seeds and a seedling. So with snow you get an early start come spring.
@Nasif Nahle August 23, 2010 at 9:04 am
re; limits on GW and CO2
Sure. There’s undoubtedly some optimal point for the biosphere as a whole. The thing of it is there doesn’t appear to be enough economically recoverable fossil fuel on the planet to reach the climate optimum by burning it.
Since it’s a reasonable question to ask what is the optimum temperature and CO2 level for the planet I’m going to go ahead and say it was the Early Eocene Climatic Optimum where average temperature was 6C warmer than today and CO2 was around 1800ppm.
Plants do not feed on warmth and CO2 alone…
Agriculture in California should really suck according to your thesis. In point of fact California has a very productive agricultural industry.
The grade for your thesis: FAIL
Close the majority of the world’s temperature measuring stations, guess at missing temperature measurements near the poles, improperly take into consideration UHI effects, throw out any historic cooling trends at specific stations (ie: Orland CA), and adjust the remaining data using 1200-km radius ‘smoothing’ over missing stations, and what have we got? The official world surface temperature record as decided by Dr. James “thumbs on the temperature scale” Hansen, better known as a compedium of corrupted thermal garbage.
This is outrageous climate doublespeak at its worst. Making a travesty of scientific research publishing.
The declining ‘greening’ – if it’s true, and let’s face it, WTFK – is due do lack of warming for ten years (and, no doubt, a myriad other adverse factors affecting the biosphere which ARE due to mankind’s activities). And they say it just goes to show that global warming CAN lead to less food production and global starvation.
They are really taking the p*ss with this one.
Who reads these ‘science journals’ anyway? Oh, that’s right, government advisors all over the planet…
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Does it include fungus in the soil?
http://www.pnas.org/content/early/2010/05/21/0912421107.abstract
A sceptic at the Guardian comments pointed out
http://www.guardian.co.uk/environment/2010/aug/19/rising-temperatures-plants-carbon?showallcomments=true#CommentKey:610aec12-8399-420b-a99a-34980ebff6c5
Would I be right in saying that this is the divergence problem all over again – another attempt to ‘hide the decline’?
The draught in the southern hemisphere could be because antarctica is increasing in extent while the arctic until recently has been decreasing in extent.Could this explain the divergence between north and south?
Dave Springer says:
August 23, 2010 at 10:56 am
Since it’s a reasonable question to ask what is the optimum temperature and CO2 level for the planet I’m going to go ahead and say it was the Early Eocene Climatic Optimum where average temperature was 6C warmer than today and CO2 was around 1800ppm.
Indeed, during the Eocene primates adaptive radiation (speciacion) happened driving 15 species to anthropoids, from which we are one species.
Nevertheless, there is something that worries me, and it is the evolution of species through the last three million years, in particular green plants and phytoplankton. It’s supposed they have adapted to the shifts of climate until present, so the question is if the species that have adapted to many climatic changes in the past would endure a climate change that could take the Earth back to ancient environmental conditions.
Obviously, a climate change of such magnitude, as the one you proposed, would favor biodiversity, but the question is: What species would disappear and what ones would survive which could undergo adaptive radiation?
Maybe the plants are trying to tell us something about the real temperature during the time of study. :o)
I was hoping to get an update on how this ‘greening of the earth’ was going, because I figured that the satellites could give a pretty good picture of the health of the biosphere. I had got used to the idea that the CO2 was helping the plants, but I must admit this paper fills out my understanding, that the temperature is actually more important than CO2 levels.
Thanks NASA.
This isn’t hiding a paleo decline, this isn’t a Pensylvanian paleo-proxy divergence tree-ring temperature records cognotive dissonance problem happening again.
No, this is real, last ten year, recent history proxy measurements disagreeing with the instrument record.
Unprecedented!
Only it isn’t – it’s just the same old sh*t.
Evolution is cleverer than you are. ~Leslie Orgel
A few million years is like yesterday to genetic memory. Any species that can’t adapt to sustained temperatures a few degrees higher than 20th century average is at an evolutionary dead-end anyway. The earth has pretty radical and rapid climate shifts between large scale glaciation and interglacial periods that cycle through in just 100,000 years or so which isn’t enough time for evolution to create novel works of genetic art. The capacity to quickly adapt to changing climate is something that’s inherent in most living things today or they wouldn’t be here.
Species typically enjoy a tenure on average of about 10 million years before going extinct. Genetic entropy inevitably takes its toll and more prototypical members of the phylum then generate something new to fill the empty niche where they then enjoy a limited tenure before their own speciality sends them into extinction. An estimated 99.9% of all species that ever existed have gone extinct. Most if not all of the modern phyla appeared rather suddenly in the Cambrian Explosion 500 mya. Few of those phyla are extinct today but countless evolutionary dead-ends along the way are footnotes in the history of life.
This is just the way of the biological world. Our insults to it are like water off a duck’s back.
Dave Springer says:
August 23, 2010 at 3:12 pm
Evolution is cleverer than you are. ~Leslie Orgel
I would answer to Orgel: “I hope so… I’m the product of evolution.” 🙂
The capacity to quickly adapt to changing climate is something that’s inherent in most living things today or they wouldn’t be here.
Species typically enjoy a tenure on average of about 10 million years before going extinct. Genetic entropy inevitably takes its toll and more prototypical members of the phylum then generate something new to fill the empty niche where they then enjoy a limited tenure before their own speciality sends them into extinction. An estimated 99.9% of all species that ever existed have gone extinct. Most if not all of the modern phyla appeared rather suddenly in the Cambrian Explosion 500 mya. Few of those phyla are extinct today but countless evolutionary dead-ends along the way are footnotes in the history of life.
Of course, extinctions favor biodiversity, according to the observations on the paleobiological records. Nonetheless, the solution to the question about what species would survive for radiating after extinctions remains unsolved.
The authors seem to be concerned that they have found evidence that CO2 absorption by plants will be reduced. I downloaded the monthly CO2 data from: http://www.esrl.noaa.gov/gmd/ccgg/trends/ and looked at the CO2 variation per year. First I detrended the data by subtracting off a 2nd order polynomial fit and then took the difference between the maximum and minimum for each year to find the yearly change. Ave range= 6.26 ppm, std. dev. 0.5
1958-2009: range = 0.016 x year -25.8 r^2 = 0.25
2001-2009: range = 0.083 x year -159.4 r^2 = 0.32
Changes in the ocean temperature probably is more important for CO2 absorption, but there is no evidence in the monthly CO2 data that there has been a decrease in CO2 uptake by plants as some of the CO2 variation is due to the yearly growing season with most of the land mass in the northern hemisphere.
SULFUR
Airborne Sulfur scatters light, which is more efficiently used by plants than direct light.
This is not just an excuse for the “Deliberate Cooling with high-altitude Sulphur Plan”, that so many have advocated (Lovelock, author of the Gaia Theory, “Dr. Ozone” Paul Crutzen, Ken Caldiera, ex-leader of the Opposition to it, the presidential GW advisor, etc.). Sulfur Cuts are a more likely cause for the starving of Millions every year with high Food Prices, than Ethanol (corn prices are not high enough, or affect Foreign Countrysides enough to explain rises that seem higher than the CAUSE). And Fishing Patterns have long been favoring the Boneless fishes over the Boned, and as Fish Bones rot & release Sulfur Dimethyls …
PS: the Bones themselves doubtless are the “mising CO2 sink” – – because the IPCC & the entire Atmospheric Modeling Community mistook the Geological process called Isostasy, for a long way of saying that water dissolves bones. Geologists do teach that, but FIRST you have to accumulate 1000s of feet thickness, form rock, rear the Sea Floor up into a Mountain range … THEN the action of H2O falling rain, moving quickly on downslopes, in gullies & streams — EROSION — in short, dissolves the CALCIUM CARBONATE.
250 million years later.
The IPCC assumes it is IMMEDIATE.
… Fishing pattern changes (at-sea Nurseries called No-Fish Zones) can restore sulfur a bit. … I’ve never seen numbers on the tonnage of Dimethyl REDUCTION — only that Natural Sulfur — volcanos are a relatively small part of the total — exceeds the man-made.
>> This raises the question of whether the MASSIVE cuts in Su “pollution” combined with the fishing patterns reducing NATURAL sources – – may have reduced the Planet BELOW the pre-industrial Sulfur levels ! DANGER !!!
Didn’t plant growth increase, by so much in the Mt. Pinutubo (high sulfur) year ,that CO2 gain dropped a factor of 5 ???
Someone asked about plant life in the ocean in the first comment.
News just out today: phytoplankton survive for 533 days on the outside of the International Space Station. Living cells not spores!
http://www.bbc.co.uk/news/science-environment-11039206
These critters haven’t been around for billions of years because they’re weak and unable to adapt. It’s ludicrous to think a slightly lower ocean pH is going to do any significant harm to the primary producers. Now it turns out the goofy things can survive for years in a vacuum. Even I’m impressed by that.
For those not wanting to read the article the little beasties did it by circling the wagons. They formed a ball and those in the center survived. That’s actually fairly common instinctive behavior for everything under attack from phytoplankton to elephants to pioneers travelling west in covered wagons. 🙂
Indeed it does remain unsolved. All, none, or something in between. Evolutionary biology and climatology are similar in that both only make educated guesses about the future based upon the past.
There’s a disclaimer commonly made when talking about a company’s economic prospects for the future: Past performance is guarantee of future performance. I have a comeback for that: Yet it remains the best predictor we have.
So based on past performance in warmer higher CO2 climes I’m more inclined to predict all or most extant species will survive but population sizes will shift downwards for some and upwards for others with the net result being much greater biomass and biodiversity.
That should be “past performance is NO gurantee of future performance”.
Jimbo said on August 23, 2010 at 1:04 pm:
The trees have been trying to tell us there’s been no noticeable warming since 1960, may even be cooling, and who’s listened to them?
😉
if you are looking for more information on USDA plant hardiness zones, there is a detailed and interactive USDA plant hardiness zone map at http://www.plantmaps.com/usda_hardiness_zone_map.php which allow you to locate your USDA zone based on zipcode or city.