BOSTON -- An international team of 32 authors from 24 institutions in eight countries has just published a study titled "Greening of the Earth and its Drivers" in the journal Nature Climate Change showing significant greening of a quarter to one-half of the Earth's vegetated lands using data from the NASA-MODIS and NOAA-AVHRR satellite sensors of the past 33 years. The greening represents an increase in leaves on plants and trees. Green leaves produce sugars using energy in the sunlight to mix carbon dioxide (CO2) drawn in from the air with water and nutrients pumped in from the ground. These sugars are the source of food, fiber and fuel for life on Earth. More sugars are produced when there is more CO2 in the air, and this is called CO2 fertilization. 
 
 "We were able to tie the greening largely to the fertilizing effect of rising atmospheric CO2 concentration by tasking several computer models to mimic plant growth observed in the satellite data," says co-author Prof. Ranga Myneni of the Department of Earth and Environment at Boston University, USA. Burning oil, gas, coal and wood for energy releases CO2 in to the air. The amount of CO2 in the air has been increasing since the industrial age and currently stands at a level not seen in at least half-a-million years. It is the chief culprit of climate change. 
 
 About 85% of the Earth's ice-free lands is covered by vegetation. The area of all green leaves on Earth is equal to, on average, 32% of the Earth's total surface area - oceans, lands and permanent icesheets combined. "The greening over the past 33 years reported in this study is equivalent to adding a green continent about two-times the size of mainland USA (18 million km2), and has the ability to fundamentally change the cycling of water and carbon in the climate system," says lead author Dr. Zaichun Zhu, a researcher from Peking University, China, who did the first-half of this study as a Visiting Scholar in the Department of Earth and Environment at Boston University, USA, together with Prof. Myneni. 
 
 Every year, about one-half of the 10 billion tons of carbon emitted in to the atmosphere from human activities remains temporarily stored, in about equal parts, in the oceans and plants. "While our study did not address the connection between greening and carbon storage in plants, other studies have reported an increasing carbon sink on land since the 1980s, which is entirely consistent with the idea of a greening Earth," says coauthor Prof. Shilong Piao of the Chinese Academy of Sciences Center for Excellence in Tibetan Plateau Earth Science, Beijing, China. 
 
 The beneficial aspect of CO2 fertilization in promoting plant growth has been used by contrarians, notably Lord Ridley (hereditary peer in the UK House of Lords) and Mr. Rupert Murdoch (owner of several news outlets), to argue against cuts in carbon emissions to mitigate climate change, similar to those agreed at the 21st Conference of Parties (COP) meeting in Paris last year under the UN Framework on Climate Change (UNFCCC). "The fallacy of the contrarian argument is two-fold. First, the many negative aspects of climate change, namely global warming, rising sea levels, melting glaciers and sea ice, more severe tropical storms, etc. are not acknowledged. Second, studies have shown that plants acclimatize, or adjust, to rising CO2 concentration and the fertilization effect diminishes over time," says co-author Dr. Philippe Ciais, Associate Director of the Laboratory of Climate and Environmental Sciences, Gif-suvYvette, France and Contributing Lead Author of the Carbon Chapter for the recent IPCC Assessment Report 5. 
 
 CO2 fertilization is only one, albeit a predominant, reason why the Earth is greening. The study also identified climate change, nitrogen fertilization and land management as other important reasons. "While the detection of greening is based on measurements, the attribution to various drivers is based on models, and these models have known deficiencies. Future works will undoubtedly question and refine our results," says coauthor Dr. Josep Canadell of the CSIRO Oceans and Atmosphere Division in Canberra, Australia and leader of the Global Carbon Project. 
 
 ### ||||| We're used to hearing about how rising carbon dioxide (CO2) levels in the atmosphere are leading to things like higher temperatures and dangerous pollution, but there's another, less commonly understood consequence to today's era-defining CO2 peak. 
 
 An international team of scientists has studied 33 years of satellite data and found that Earth is actually getting significantly greener as a result of rising carbon dioxide levels, with greater carbon emissions over the past three decades leading to a huge increase in the amount of leaves on plants and trees. 
 
 "We were able to tie the greening largely to the fertilising effect of rising atmospheric CO2 concentration by tasking several computer models to mimic plant growth observed in the satellite data," said researcher Ranga Myneni from Boston University. 
 
 But how are airborne pollutants spurring vegetation growth? The process, called the carbon fertilisation effect, results from leaves absorbing CO2 from the air as part of photosynthesis. With greater levels of carbon in the atmosphere, plants and trees and even crops actually grow faster, particularly in warm climates. 
 
 And with the levels of carbon in the atmosphere as high as they are now, that's seen a massive increase in the amount of vegetation over the surface of the planet. 
 
 "The greening over the past 33 years reported in this study is equivalent to adding a green continent about two times the size of mainland USA (18 million km2), and has the ability to fundamentally change the cycling of water and carbon in the climate system," said one of the team, Zaichun Zhu from Peking University in China. 
 
 As a result of the growth in recent decades, vegetation now covers almost a third (32 percent) of the planet's total surface area, occupying about 85 percent of all ice-free land. 
 
 But while extra greenery – and its ability to absorb atmospheric carbon – sounds like a positive for the environment, the scientists warn that this side effect of high carbon levels will only be temporary, and won't ultimately help against other consequences of climate change, such as severe weather, and rising temperatures and sea levels. 
 
 "[S]tudies have shown that plants acclimatise, or adjust, to rising CO2 concentration and the fertilisation effect diminishes over time," said Philippe Ciais from the Laboratory of Climate and Environmental Sciences in France. 
 
 Nor is CO2 the only factor behind the current green trends. The scientists say nitrogen use in agricultural fertilisers, climate change generally, and land management also contribute to the phenomenon in lesser amounts. 
 
 The findings, reported in Nature Climate Change, will hopefully serve as another pressing reminder of the importance of lowering carbon emissions, in the same week that world leaders have come together to sign the Paris climate deal. 
 
 "This is a snapshot of humans' global influence on the functioning of the entire global biosphere," one of the team, Pep Canadell from the CSIRO in Australia, told Anna Salleh at the ABC. "The growth of CO2 in the atmosphere is almost exclusively due to fossil fuel burning and deforestation." ||||| Earth getting greener due to rising carbon dioxide levels, global snapshot shows 
 
 Updated 
 
 Rising carbon dioxide levels in the atmosphere have increased plant growth across the planet over the past three decades, a new study has found. 
 
 Key points A few areas on Earth have browned but the vast majority have greened 
 
 Plant coverage has grown by 18 million square kilometres in a few decades 
 
 The main cause is increase in atmospheric CO2 
 
 Nitrogen from agricultural fertilisers has also contributed 
 
 The most comprehensive modelling of remote sensing data so far shows the area on Earth covered by plants in this time has increased by 18 million square kilometres — about 2.5 times the size of the Australian continent — largely due to the fertilising effect of carbon dioxide (CO2). 
 
 "[The greening] has the ability to fundamentally change the cycling of water and carbon in the climate system," said Dr Zaichun Zhu, from Peking University in China and lead author of the new study, which appears today in the journal Nature Climate Change. 
 
 Carbon fertilisation is the dominant process for greening across the globe, particularly in the tropics because there's so much leaf area there. Dr Pep Canadell 
 
 "This is a snapshot of humans' global influence on the functioning of the entire global biosphere," said co-author CSIRO's Dr Pep Canadell of the Global Carbon Project. 
 
 The new findings come from analysis of data from the past 33 years taken by three different satellite missions that measured the green light reflected by photosynthesising leaves. 
 
 Dr Canadell said the remote sensing data was run through 10 global environmental change models to identify the cause of the greening. 
 
 About 85 per cent of Earth's ice-free land is covered by plants, and each year photosynthesis soaks up about one quarter of the nearly 10 billion tonnes of carbon emitted by humans. 
 
 Drs Zhu, Canadell and colleagues found that the 46 parts per million increase in atmospheric CO2 between 1982 and 2009 was responsible for 50 to 70 per cent of the observed greening. 
 
 "Carbon fertilisation is the dominant process for greening across the globe, particularly in the tropics because there's so much leaf area there," Dr Canadell said. 
 
 Scientists have long established humans as a key source of atmospheric CO2 through the use of chemical signatures that distinguishes carbon from different sources. 
 
 "The growth of CO2 in the atmosphere is almost exclusively due to fossil fuel burning and deforestation," said Dr Canadell. 
 
 The new study found other causes of the greening, including nitrogen from agricultural fertilisers. 
 
 'Surprising' finding given increase in droughts 
 
 Dr Canadell said the greening has surprised scientists who expected to see more browning, given the increase in droughts associated with global warming. 
 
 While the researchers found between 25 to 50 per cent of all vegetated areas of the land have become greener, only 4 per cent have become browner. 
 
 These included Mongolia, Argentina and areas of North America close to Alaska. 
 
 While south-eastern Australia also showed browning, overall the Australian continent was greening, said Dr Canadell. 
 
 While a greener Earth might seem like a positive from CO2-induced global warming, along with milder winters and longer growing seasons, he said there were many more negative impacts — including rising sea levels and severe weather. 
 
 "These will eventually outweigh by far any benefit from the greening," he said. 
 
 Topics: climate-change, science-and-technology, agricultural-crops, forestry, rain-forests-and-forest, china 
 
 First posted
– Dozens of scientists were shocked to find a dramatic increase in plant life around the world over the past 33 years instead of the global-warming-related "browning" they expected to find in their analysis of satellite data, Australia's ABC reports. According to a press release, a study published Monday in Nature Climate Change found "significant greening" over 25% to 50% of Earth's plant-bearing surface (some 4% did grow browner). "The greening ... reported in this study is equivalent to adding a green continent about two-times the size of mainland USA," says Dr. Zaichun Zhu, the study's lead author. The reason for the greening is what is known as the carbon fertilization effect: an increase in carbon dioxide in the atmosphere means plants, which use the gas in photosynthesis, grow faster, Science Alert reports. In what's good news for plants, there's currently more CO2 in the atmosphere than at any time in at least the past 500,000 years. "This is a snapshot of humans' global influence on the functioning of the entire global biosphere," study coauthor Dr. Pep Canadell tells ABC. However, what's good news for plants isn't necessarily good news for anything else on the planet, as Canadell cites fossil fuel burning and deforestation as "almost exclusively" causing the rise of CO2 in the atmosphere. CO2 emissions are the main cause of climate change, the other effects of which—drought, rising seas, deadly weather—far outweigh the benefits of what scientists say is a temporary increase in plant life. (Carbon dioxide might also be making us dumber at the office.)