Claim:
“The current warming period began about 1800 at the end of the little ice age, long before there was an appreciable increase of CO2. There have been similar and even larger warmings several times in the 10,000 years since the end of the last ice age. These earlier warmings clearly had nothing to do with the combustion of fossil fuels. The current warming also seems to be due mostly to natural causes, not to increasing levels of carbon dioxide. Over the past ten years there has been no global warming, and in fact a slight cooling. This is not at all what was predicted by the IPCC models.”
— Testimony to Senate Energy Committee by William Happer, the Cyrus Fogg Bracket Professor of Physics at Princeton University, February 25, 2009
Truth:
William Happer is a physics professor at Princeton University, but he is also the Chairman of the Board at the George C. Marshall Institute, a conservative think tank in Washington, DC, which has been a leading voice in opposing global warming action. Between 1998 and 2006, the Marshall Institute received $715,000 from ExxonMobil.
Mr. Happer’s testimony before the Senate Energy Committee was misleading on a variety of fronts. The planet has indeed warmed and cooled in cyclical fashion for millennia. But that’s not the point. The inference – that the current warming trend is just another naturally occurring warm cycle – is not true, as this post from Climate 411 explains.
Here is a graphic from that post that shows the extent of the current warming trend:
The claim that the current warming trend began “long before there was an appreciable increase of CO2” is directly challenged by this graphic, as you can see a strong correlation between the rising blue line (CO2 concentrations) the more jagged but none-the-less rising red line (temperature).
And, as we point out in Climate 411, the only explanation for this warming is the rise in greenhouse gas concentration from burning fossil fuels and deforestation.
The claim that there has been no global warming, and in fact a slight cooling, over the last decade is also very misleading. In fact, the warmest decade on record is the last ten years.
While 2008 was cooler than the previous year, it still ranked as either the 9th warmest year on record (according to NASA) or tied for the 8th warmest year on record (according to NOAA). And, according to NASA, part of the reason for a slightly cooler year was, “due to a strong La Niña that existed in the first half of the year. La Niña and El Niño are opposite phases of a natural oscillation of tropical temperatures, La Niña being the cool phase.” (see NASA report).
To claim that warming has slowed based on year-to-year fluctuations in global temperature is ignoring the impact of other cyclical “climate modes” – such as La Niña – and is blatantly misrepresenting the longer-term trend.
A new study out of the University of Wisconsin-Milwaukee examines this very question and concludes that the interactions of 4 known climate modes that have some cyclic behavior work together to affect global temperature.
The report suggests that when these modes get in synch, there are global climate shifts. Their conclusion that global temperatures have been flat is due to the short time scale they’re using to look for trends and the fact that 2008 was a fairly “cold” year.
In case there is any confusion about this, here is the report’s final paragraph:
“Finally, it is vital to note that there is no comfort to be gained by having a climate with a significant degree of internal variability, even if it results in a near-term cessation of global warming. It is straightforward to argue that a climate with significant internal variability is a climate that is very sensitive to applied anthropogenic radiative anomalies [GHGs]. If the role of internal variability in the climate system is as large as this analysis would seem to suggest, warming over the 21st century may well be larger than that predicted by the current generation of models, given the propensity of those models to underestimate climate internal variability.”
One last point — Professor Happer’s attempt to undermine the IPCC in his last sentence borders on obnoxious and only serves to undermine his entire presentation.
IPCC models are designed for projecting long-term climate trends and don’t attempt to look at short-term internal climate variation. There are plenty of models that are beginning to tackle that challenge.
But, it is fundamentally wrong and, yes, obnoxious to criticize a model that’s designed to explore trends over many decades for not getting a few years right. Just because April 7th is cooler than April 4th one year doesn’t mean that August will be colder than January.
