Um, so, coal is good now? Washington Post:
A new study published this week offering a fresh take on what may have driven a temporary, 10-year slowdown in global warming reinforces the scientific hypothesis that human activities are contributing to long-term global warming.
Researchers have published several studies seeking to explain a relative plateau in global warming that took place between 1998 and 2008, compared to the longer-term period since the beginning of the industrial revolution during which the climate has warmed significantly. Some studies have focused on “internal climate variability” that is poorly understood and poorly anticipated, others on changes in water vapor in the upper levels of the atmosphere.
But the new study, by American and Finnish researchers, says the answer lies mainly in the quickening pace of coal consumption in Asia, particularly in China, and the air pollution that is causing.
Reflecting China’s rapid economic growth, Chinese coal consumption more than doubled in just four years between 2003 and 2007, causing a 26 percent jump in global coal consumption during this period, the study states. This added coal use, much of it in the absence of stringent air pollution controls, caused more sulfur emissions to go into the atmosphere, the study states. Unlike greenhouse gases such as carbon dioxide, which are also emitted by coal-fired power plants, sulfate aerosols act as a cooling influence on the climate, by reflecting incoming solar radiation back toward space.
The study finds that the surge in these emissions, plus a weakening phase of the 11-year solar cycle, and an assist from La Nina conditions in the Pacific Ocean, helped to temporarily reduce the warming effects of greenhouse gases.
“What’s going on is, human activities do two things: They cool the planet and they warm the planet. People normally just focus on the warming effect of CO2 (carbon dioxide), but during the Chinese economic expansion there was a huge increase in sulfur emissions,” study lead author Robert K. Kaufmann of Boston University, told the Associated Press.
The rest here.