Higher coal use could cause droughts in Asia
Along with all the negative health effects associated with coal-burning, the study published in the Journal of Climate concludes that if China and India keep increasing their share of coal-derived power, precipitation over a large expanse of land masses would be suppressed, resulting in drought conditions. The researchers looked at two scenarios: one, a high-coal use future, where energy demand in Asia necessitates rapid increases in the burning of coal; and a second scenario where impacts of coal use are shifted by using cleaner-burning natural gas and renewables.
In the high-coal-use scenario where emissions double their year 2000 benchmark levels from 2030 to 2100, increased sulfate aerosols – mostly black carbon and sulfur dioxide (SO2) – released into the atmosphere would offset warming from greenhouse gas emissions including carbon dioxide, resulting in a cooling effect throughout the Northern Hemisphere, along with South Asia and Southeast Asia. The cooling effects would suppress rainfall.
“For the high-emissions scenario, we found reductions in rainfall across much of Asia, especially East Asia (including China) and South Asia (including India), and a remote effect leading to a possible increase in rainfall in Australia as well as a suppression of rainfall in the Sahel region of Africa,” says Benjamin Grandey, a research scientist in Wang’s research group at the Singapore-MIT Alliance for Research and Technology. “We see more reductions in rainfall than increases, especially in regions already struggling with water resources.”
Of course, whether the study’s scenario comes to fruition is highly speculative, considering the moribund coal market and recent efforts made in China to combat pollution. In Beijing, for example, all coal-fired power plants will be banned by 2020. Still, as MIT News points out, coal remains the primary source of electricity throughout Asia.
For the high-emissions scenario, we found reductions in rainfall across much of Asia, especially East Asia (including China) and South Asia (including India)
In December the International Energy Agency reported that “peak coal” in China is drawing near, noting that coal consumption has fallen for the last two years.
Lately China, the world’s largest coal consumer, is stepping up efforts to shrink both oversupply and a worsening pollution crisis in its major cities by reducing the number of working days for its coal miners to 276 a year from 330.
Between them, China and India accounted for 98% of the increase in world coal trade between 2008 and 2013, according to the U.S. Energy Information Administration (EIA). However the administration last November noted that data for 2014 and 2015 indicated a reversal of this trend, with declines in China’s coal imports currently on pace to more than offset slight increases in other countries in both years.