Has Earth Climate Warming Trend Stopped?

Former BBC science journalist and astrophysicist Dr. David Whitehouse says in spite of rising atmospheric CO2 the average temperate on planet Earth is not rising.

With only few days remaining in 2007, the indications are the global temperature for this year is the same as that for 2006  there has been no warming over the 12 months. But is this just a blip in the ever upward trend you may ask? No. The fact is that the global temperature of 2007 is statistically the same as 2006 as well as every year since 2001. Global warming has, temporarily or permanently, ceased. Temperatures across the world are not increasing as they should according to the fundamental theory behind global warming  the greenhouse effect. Something else is happening and it is vital that we find out what or else we may spend hundreds of billions of pounds needlessly.

Whitehouse is not making a radical claim. He's just not putting the same spin on the facts that you'll find in most media reports about temperature trends. A recent BBC report (not by Whitehouse) has a chart showing 1998 was warmer than any year since and 6 years in that period were slightly warmer than 2007. Their spin is that the 2007 temperature shows that global warming is a confirmed trend. Um, well, on one hand 2007 didn't return the world to cooler temperature levels from earlier decades. But on the other hand the amount of carbon dioxide in the atmosphere has gone up a lot since 1998. So why hasn't the average global temperature for 2007 easily beat the 1998 number? (not trying to imply an answer btw - I'm just full of questions)

Dr. Whitehouse says the world might be cooling due to reduced solar energy output.

Something is happening to our Sun. It has to do with sunspots, or rather the activity cycle their coming and going signifies. After a period of exceptionally high activity in the 20th century, our Sun has suddenly gone exceptionally quiet. Months have passed with no spots visible on its disc. We are at the end of one cycle of activity and astronomers are waiting for the sunspots to return and mark the start of the next, the so-called cycle 24. They have been waiting for a while now with no sign it's on its way any time soon.

So maybe atmospheric carbon dioxide (CO2) buildup really has a warming effect. But that warming effect is getting offset by a cooling effect caused by less solar radiation.

But recently the Sun's internal circulation has been failing. In May 2006 this conveyor belt had slowed to a crawl  a record low. Nasa scientist David Hathaway said: "It's off the bottom of the charts... this has important repercussions for future solar activity." What's more, it's not the only indicator that the Sun is up to something.

Back during the Little Ice Age era (starting perhaps as early as the 13th century and ending in the 19th century) the Earth experienced periods of reduced sunspot activity including during the Sporer Minimum (14501540) and Maunder Minimum (1645-1715). That period featured a Thames River that froze over in winters and lots of hunger and death from food shortages in Europe. Another Little Ice Age would cause problems on a scale rivaling or exceeding some of the problems predicted from global warming.

Reduced sunspot activity isn't necessarily a reason for complaisance about atmospheric CO2 buildup. Even if our pollution is buffering the effects of reduced solar output at some point the sun will probably kick back up again and the CO2 will still be there. Though if the Sun causes huge climate changes (and that appears to be the case) then we need to develop the means to rapidly dial up and down the greenhouse effect in order to reduce the size of climate swings caused by solar output fluctuations.

Another possibility: Maybe increased sulfur aerosol pollution from China burning more coal is generating a cooling effect that is partially canceling the warming effect of CO2 buildup. This seems plausible at least. China's rate of expansion has caused a huge increase in a wide range of emissions and not just CO2 emissions.

Along with aluminum and cement, steel is the biggest reason China added 90 gigawatts of power generation capacity this year, the third year in a row in which it will increase its power output by more than the total capacity of Britain. About 85 percent of those new power plants burn coal. The International Energy Agency, an energy policy and research group in Paris, had predicted as recently as a few years ago that China's carbon emissions would not reach those of the United States until 2020. But industrial production and coal use have grown so much faster than estimated that the agency now thinks China took the lead this year.

Production which has been shifted from the West to China (many economists call this "free trade") is cheaper in China in part because China tolerates far more pollution per unit of production.

A study by researchers at Carnegie Mellon University found that if all the goods that the United States imported between 1997 and 2004 had been produced domestically, America's carbon emissions would have been 30 percent higher. A separate study for the European Parliament examined the transfer of steel production to China from Germany. It found that China's less efficient steel mills, and its greater reliance on coal, meant that it emitted three times as much carbon dioxide per ton of steel as German steel producers. Pollution has not only shifted to China, in other words, but intensified even faster than the country's rapidly expanding output.

So types of pollutants that reflect away the sun's energy are another possible explanation for the seeming end of the warming trend in Earth average temperature. Aside: Britain is also in the ranks of countries that have basically exported a lot of their pollution to China.

Update: What I want to know: How noisy is the data for measuring the average temperature of the Earth's atmosphere? Could noise in the data make a real warming trend seem to stop? Given that temperature over a period of centuries varies a great deal naturally one should expect natural trends to sometimes work with and work against human-caused trends and therefore make human-caused trends harder to detect and confirm. There are real limits on our ability to know what is going on.

Update II: See the comments section for a comment about how volcanic eruptions make the temperature data noisy. Also, Peak Coal might end the whole fossil fuels emissions debate in a couple of decades. Peak Oil and Peak Natural Gas will probably happen sooner. For more on Peak Coal see here and here and here and here.