Memos & Research


Mar 9, 2017

Anjan Mukherjee

EPA Administrator Scott Pruitt said this morning that carbon dioxide is not a primary contributor to global warming:

“I think that measuring with precision human activity on the climate is something very challenging to do and there’s tremendous disagreement about the degree of impact. So no, I would not agree that it’s a primary contributor to the global warming that we see.” [WATCH]

But government agencies – including Scott Pruitt’s EPA – all assert the science of climate change:

EPA FACT CHECK: “Carbon dioxide is the primary greenhouse gas that is contributing to recent climate change.”

  • “Research indicates that natural causes do not explain most observed warming, especially warming since the mid-20th century. Rather, it is extremely likely that human activities have been the dominant cause of that warming.”

NOAA FACT CHECK: A large body of evidence supports the conclusion that human activity is the primary driver of recent warming. This evidence has accumulated over several decades, and from hundreds of studies.

  • The first line of evidence is our basic physical understanding of how greenhouse gases trap heat, how the climate system responds to increases in greenhouse gases, and how other human and natural factors influence climate.
  • The second line of evidence is from indirect estimates of climate changes over the last 1,000 to 2,000 years. These estimates are often obtained from living things and their remains (like tree rings and corals) which provide a natural archive of climate variations. These indicators show that the recent temperature rise is clearly unusual in at least the last 1,000 years.
  • The third line of evidence is based on comparisons of actual climate with computer models of how we expect climate to behave under certain human influences. When climate models are run with historical increases in greenhouse gases, they show gradual warming of the Earth and ocean surface, increases in ocean heat content, a rise in global sea level, and general retreat of sea ice and snow cover.

NASA FACT CHECK: Ninety-seven percent of climate scientists agree that climate-warming trends over the past century are very likely due to human activities, and most of the leading scientific organizations worldwide have issued public statements endorsing this position.”

  • “The current warming trend is of particular significance because most of it is very likely human-induced and proceeding at a rate that is unprecedented in the past 1,300 years.”
  • Compelling evidence of climate change comes from: Sea level rise, Increasing global temperatures, Warming oceans, Shrinking ice sheets, Declining Arctic sea ice, Glacial retreat, Ocean acidification and Decreased snow cover.