Scientists Overwhelmingly Agree That Human Activities Are Causing Climate Change

While much global warming science is constantly changing as researchers make new discoveries or revise old theories, the answer to the basic question of whether human activities are responsible for changes in the earth’s climate is nearly indisputable: anthropogenic greenhouse gases (GHG) are causing, at least in part, the earth to warm.  Whether one looks to a recent study that investigated individual climate researchers’ positions on the issue, or to a somewhat dated joint pronouncement on climate change issued by the science academies of numerous nations, the scientific community seems close to unanimity as far as the cause of the phenomenon.
   
A study (fn1) conducted in 2009 by researchers from Stanford University and other institutions, focused on some 900 climate researchers who were publishing in the field.  After grouping each scientist into either a camp that believed in human-caused global warming or a camp that was unconvinced of the notion, the study’s authors then searched for factors showing general acceptance of each scientist’s climate work; one factor consisted of how often the researcher had been cited in other published materials.  The study concluded that the overwhelming majority -- 97 to 98% -- of climate scientists who were most active in the field (as far as publishing) were convinced of the existence of human-caused climate change.  In addition, those scientists who were not convinced of human-caused global warming possessed less credibility in the scientific world than their colleagues who were convinced.  

Looking at the broader scientific community, a statement (fn2)  was released in 2005 by the science academies of Brazil, Canada, China, France, Germany, India, Italy, Japan, Russia, United Kingdom, and the United States indicating  that there was “strong evidence that significant global warming is occurring,” an assertion that essentially supported the findings of the Intergovernmental Panel on Climate Change (IPCC)(fn3) .  The statement by the 11 science academies further stated that it was likely that most of recent climate change was due to human actions, and called on the world leaders to take steps quickly to reduce GHG emissions.
       
For anyone to claim that there is a lack of scientific consensus on whether humans are responsible for the warming of the earth amounts to either intellectual dishonesty or just plain ignorance.

1 See http://www.pnas.org/content/107/27/12107.full
2 See http://nationalacademies.org/onpi/06072005.pdf
3 The IPCC, formed by the United Nations and World Meteorological Organization, releases periodic reports analyzing, in part, the current state of knowledge in climate change science.  The IPCC is composed of thousands of scientists from around the world who volunteer their time.