Study says global warming not hurting plant growth
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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,” said report author Craig Idso, Ph.D., founder and chairman of the Center for the Study of Carbon Dioxide and Global Change and a senior fellow for environment policy at The Heartland Institute, which contends its goal is to discover, develop, and promote free-market solutions to social and economic problems. The institute has a history of disagreeing with contentions of global climate change.
“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,” Idso said. “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:
- The productivity of the planet’s terrestrial biosphere, on the whole, has been increasing with time, revealing a great greening of the earth that extends throughout the entire globe.
- Satellite-based analyses of net terrestrial primary productivity (NPP) reveal an increase of around 6 to 13 percent since the 1980s.
- There is no empirical evidence to support the model-based IPCC claim that future carbon uptake by plants will diminish on a global scale due to rising temperatures. In fact, just the opposite situation has been observed in the real world.
- 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.
- There is compelling evidence that the atmosphere’s rising CO2 content—the chief reason behind the IPCC’s concerns about the future of the biosphere, due to the indirect threats the IPCC claims will result from CO2-induced climate change—is actually most likely the primary cause of the observed greening trends.
- 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 the recent “greening of the earth” observed by a host of scientists will likely continue. 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 here at The Heartland Institute, or at the Web site of the Center for the Study of Carbon Dioxide and Global Change. Questions about the report can be addressed to Idso at contactus@co2science.org.
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