Climate Change and Global Warming

Some FAQs and where to go for more information:

What is Climate Change? Scientists generally discuss climate change in the context of statistical change over long time periods, regardless of the cause. For example, the end of the last glacial period (about 12,000 years ago) is called the Pleistocene. At that time, a massive ice sheet covered what is now Canada and much of northern North America. An ice sheet miles thick—now that’s climate change!

What’s Global Warming? NASA refers to global warming as the “the average global surface temperature increase from human emissions of greenhouse gases.” (NASA).

I thought scientists disagreed about global warming? First, no widely respected scientific body disagrees with the basic idea that human-induced changes in greenhouse gases have lead to global increases in temperature. So-called disputes are much more common in the popular media. The IPCC (Intergovernmental Panel on Climate Change), an authoritative scientific body set up by the U.N., reported the following in their 2013 Summary for Policy Makers: “Warming of the climate system is unequivocal, and since the 1950’s, many of the observed changes are unprecedented over decades to millennia. The atmosphere and ocean has warmed, the amounts of snow and ice have diminished, sea level has risen, and concentration of greenhouse gases has increased.” If you look at this IPCC report, note that the scientists use terms such as “high confidence” or “medium confidence” in their conclusions. For instance, that 1983-2012 was likely the warmest 30 year period in the last 1400 years is reported with medium confidence. In contrast, ocean warming is discussed in terms of high confidence. These differences in “confidence” should not be interpreted as disagreement between scientists. Instead, these distinctions reflect issues such as availability of data over long periods of time and variability in findings over time and in difference places.

There’s so much emphasis on the IPCC reports. Who are the scientists who worked on them? It’s always important to consider the source of any information. Thousands of IPCC experts worldwide contribute voluntarily to producing these reports. Chapters are written by scientists and others recognized by the excellence of their work in various aspects (e.g., atmospheric changes, socio-economic effects). They rely heavily on peer-reviewed published sources. (Peer-review is the process by which scientists’ papers are critiqued by experts with no conflict of interest with the authors.) NOAA – the National Oceanographic and Atmospheric Association – calls the IPCC “the most senior and authoritative body providing scientific advise to policy makers”.

What is climate change denial? Various groups, some with a great deal of money, have tried to downplay or dismiss the scientific consensus on warming, its importance, and the degree to which humans are responsible. It’s critical to recognize that denial is very different from skepticism. Scientists are trained to be skeptical – to question sources of information, the quality of the data, and so on. Scientific experts may disagree about interpretation of the same information (such as inferring human evolution from ancient bones). This is part of the process of science. But climate change denial is very different from this. Denialists know they are right and they cherry-pick information to prove what they claim. They recycle old myths, rely on fake experts and non-peer reviewed sources, and basically invent conspiracy and controversy where none exists.

Some sources for additional Information Start Here

More detailed sourcesEPAIPCC Summary 2013 for Policy MakersNational Academy of ScienceNOAA State of the Climate

Books on my bookshelf*


  • Heatstroke: Nature in an Age of Global Warming (Anthony D. Barnosky)
  • The Weather Makers (Tim Flannery)
  • Storms of My Grandchildren (James Hansen)
  • While Glaciers Slept (M. Jackson)
  • Climate Cover-Up (James Hoggan)
  • Field Notes from a Catastrophe (Elizabeth Kolbert)
  • The Race for What’s Left (Michael T. Klare)
  • The Hockey Stick and the Climate Wars (Michael E. Mann)
  • The Global Warming Reader (Bill McKibben)
  • Merchants of Doubt (Naomi Oreskes and Eric M. Conway)
  • The Inquisition of Climate Science (James Lawrence Powell)
  • Climate Change Denial (Haydn Washington and John Cook)


  • Love in the Time of Climate Chamge (Brian Adams)
  • Flight Behavior (Barbara Kingsolver)
  • Solar (Ian McEwan)
  • Odds Against Tomorrow (Nathaniel Rich)
  • Far North (Marcel Therox)
  • For over 300 titles, click on the link.