A new study by the Center for the Study of Carbon Dioxide and Global Change -- The State of Earth's Terrestrial Biosphere: How is it Responding to Rising Atmospheric CO2 and Warmer Temperatures? -- refutes claims by the United Nations' Intergovernmental Panel on Climate Change (IPCC) that global warming is stressing Earth's natural and agro-ecosystems by reducing plant growth and development.
"Such claims are simply not justified when one examines the balance of evidence as reported in the peer-reviewed scientific literature," says Dr. Craig Idso, author of the report. "Far from being in danger, the vitality of global vegetation is better off now than it was a hundred years ago, 50 years ago, or even a mere two-to-three decades ago." And "the observed increases in vegetative productivity and growth are happening in spite of all the many real and imagined assaults on Earth's vegetation that have occurred during this time period, including wildfires, disease, pest outbreaks, deforestation, and climatic changes in temperature and precipitation."
Specific findings in the meta-analysis examining hundreds of scientific studies on the subject include:
|- Satellite-based analyses of net terrestrial primary productivity (NPP) reveal an increase of around 6-13% since the 1980s.|
|- Earth's land surfaces were a net source of CO2-carbon to the atmosphere until about 1940. From 1940 onward, however, the terrestrial biosphere has become, in the mean, an increasingly greater sink for CO2-carbon.
- Over the past 50 years, for example, global carbon uptake has doubled from 2.4 ± 0.8 billion tons in 1960 to 5.0 ± 0.9 billion tons in 2010.
3. There is compelling evidence that the atmosphere's rising CO2 content - which the IPCC considers to be the chief reason behind all of their concerns about the future of the biosphere (via the indirect threats they claim it poses as a result of CO2-induced climate change) - is actually most likely the primary cause of the observed greening trends.
4. In the future, Earth's plants should be able to successfully adjust their physiology to accommodate a warming of the magnitude and rate-of-rise that is typically predicted by climate models to accompany the projected future increase in the air's CO2 content. And factoring in the plant productivity gains that will occur as a result of the aerial fertilization effect of the ongoing rise in atmospheric CO2, plus its accompanying transpiration-reducing effect that boosts plant water use efficiency, the world's vegetation possesses an ideal mix of abilities to reap a tremendous benefit in the years and decades to come.
Given these findings, the report contends that the recent "greening of the Earth" observed by a host of scientists will likely continue throughout the years and decades to come. Government leaders and policy makers should take notice of the findings of this important new assessment on the state of the Earth's terrestrial biosphere.
The report can be viewed or downloaded at the website of the Center for the Study of Carbon Dioxide and Global Change at http://www.co2science.org/education/reports/greening/greening.php. Questions about the report can be addressed to Dr. Craig Idso at the email address email@example.com.