jim mcnamara said:
The consensus (meaning virtually all of the climate scientists) is that human activity is the driver for climate change.
klimatos said:
You might want to qualify that rather bald statement ("human activity is the driver for climate change") somewhat! Most paleo-climatologists might take exception to it. There is good scientific evidence for climate change throughout the Earth's history.
Hi klimatos:
I believe that your comment regarding jim mcnamara's quote is based on a misunderstanding. Your are correct that humans had no significant influence on climate change before about 1850, but the consensus mentioned in klimatos's quote relates to what has been happening since about 1950. I came across these dates in a authoritative article I was reading recently, but unfortunately it will take me a while to find it again so I can cite it.
ADDED
https://climate.nasa.gov/scientific-consensus
Multiple studies published in peer-reviewed scientific journals1 show that 97 percent or more of actively publishing climate scientists agree: Climate-warming trends over the past century are extremely likely due to human activities. In addition, most of the leading scientific organizations worldwide have issued public statements endorsing this position. The following is a partial list of these organizations, along with links to their published statements and a selection of related resources.
American Geophysical Union
"Human‐induced climate change requires urgent action. Humanity is the major influence on the global climate change observed over the past 50 years. Rapid societal responses can significantly lessen negative outcomes." (Adopted 2003, revised and reaffirmed 2007, 2012, 2013)
5
[5] https://sciencepolicy.agu.org/files/2013/07/AGU-Climate-Change-Position-Statement_August-2013.pdf
Human activities are changing Earth’s climate. At the global level, atmospheric concentrations of carbon dioxide and other heat‐trapping greenhouse gases have increased sharply since the Industrial Revolution. Fossil fuel burning dominates this increase. Human‐caused increases in greenhouse gases are responsible for most of the observed global average surface warming of roughly 0.8°C (1.5°F) over the past 140 years. Because natural processes cannot quickly remove some of these gases (notably carbon dioxide) from the atmosphere, our past, present, and future missions will influence the climate system for millennia.
U.S. Global Change Research Program
"The global warming of the past 50 years is due primarily to human-induced increases in heat-trapping gases. Human 'fingerprints' also have been identified in many other aspects of the climate system, including changes in ocean heat content, precipitation, atmospheric moisture, and Arctic sea ice." (2009, 13 U.S. government departments and agencies)
12
[12]
https://downloads.globalchange.gov/usimpacts/pdfs/climate-impacts-report.pdf (pg 13)
Regards,
Buzz