What do the scientists (in peer reviewed journals) say about global warming?
To set the stage, here is an excerpt from White House press gaggle on February 20, 2006 on board Air Force One:
Q There was a report on television last night about the — about global warming and demands contribution to the atmosphere, and so on, was — is the U.S. government — does the U.S. care that the polar ice caps are melting? And this whole sort of energy reform that you’re putting forth, does the environment play any part in it?
MR. HUBBARD: I’ll let Scott take that one.
MR. McCLELLAN: What was your question.
Q It was a story on “60 Minutes” last night about global warming and — what’s the administration’s position on any of this energy reform, or whether it’s –
MR. McCLELLAN: The United States is leading the way in investing in the kind of technologies to help us address greenhouse gas emissions. That’s something we — remember, we’re on track to meet the President’s goal of reducing greenhouse gas intensity that he outlined. And we also have joined in partnerships around the world to invest in research and development when it comes to climate change. It’s an issue that the President takes seriously, and we announced the Asia Pacific Partnership, remember, and that is an initiative to help lead the way to address some of these issues associated with climate change.
Q Do you take Michael Crichton on the issue seriously?
MR. McCLELLAN: What’s your question?
Q There’s a story –
MR. McCLELLAN: I think what I can point to — I’m not going to get into talking about private meetings he’s had, but look at the initiatives we’ve outlined, look at the leadership the President is providing to address the challenges of climate change. It is an issue that we take seriously, and that’s why we’ve been investing billions in research and development to better understand the science of climate change. That’s why we’ve initiated partnerships, like the Asia Pacific Partnership, to address these issues, as well.
Q But Michael Crichton as an expert or a novelist the President enjoys reading?
MR. McCLELLAN: The President read his book, and he was glad to have the opportunity to visit with him.
Q — believes as expert opinion?
MR. McCLELLAN: I think you should look at what we outlined, Jessica. If you want to ask the President about it, you are — you’re welcome to do that at some point. But I’m not going to get into talking about private meetings that he has.
Thanks. [Emphasis added -- mdc]
Well, I’m an admirer of Michael Crichton‘s books, including The Andromeda Strain and Airframe, so I was intrigued when I heard he’d written a book critiquing the idea of global warming. After reading a little, I thought I’d check on what the scientists have to say.
(By the way, Crichton has an A.B. from Harvard College, M.D. from Harvard Medical School, but no degree in atmospheric sciences. The NRC is a private nonprofit associated with the National Academy of Sciences that provide advice to the U.S. Government under Congressional charter.) From the report:
Figure S-1: From NRC (2006).
The confidence bands associated with each of the projections are displayed in subsequent figures in the report.
There is a related question of whether warming is due to human activities or the end of a little ice age. Here is the summary for Chapter 10, entitled “Climate Forcings and Climate Models”.
- The main external climate forcings experienced over the last 2,000 years are volcanic eruptions, changes in solar radiation reaching the Earth, and increases in atmospheric greenhouse gases and aerosols due to human activities.
- Proxy records are available for reconstructing climate forcings over the last 2,000 years, but these climate forcing reconstructions are associated with as much uncertainty as surface temperature reconstructions.
- Greenhouse gases and tropospheric aerosols varied little from A.D. 1 to around 1850. Volcanic eruptions and solar fluctuations were likely the most strongly varying external forcings during this period, but it is currently estimated that the temperature variations caused by these forcings were much less pronounced than the warming due to greenhouse gas forcing since the mid 19th century.
- Climate model simulations indicate that solar and volcanic forcings together could have produced periods of relative warmth and cold during the preindustrial portion of the last 1,000 years. However, anthropogenic greenhouse gas increases are needed to simulate late 20th century warmth.
Food for thought, as projected temperatures for Tuesday and Wednesday rise to 98 degrees here in Washington, DC, 12 degrees above the historical mean for August. See here for discussion of global record breaking temperatures.