Climate change is a major contributor to the widespread heat waves across the globe this year and will cause more extreme weather to come in the future if the issue remains unresolved, a U.S. expert on climate change has warned.
A multitude of cities around the northern hemisphere have been sweating in an unusually hot summer this year, including Shanghai, Paris and Los Angeles. The sweltering heat, often accompanied by droughts and floods, brought about losses in lives and properties.
One fundamental cause of this round of heat waves is climate change, Prof. Ronald L. Sass with Rice University told Xinhua in a recent interview.
"The weather has been changing since about 1850s, but it has been changing very slowly. By 1980 or 1990, we began to see an accelerating effect of the climate change. The accelerating effect keeps accelerating, so the climate change is becoming more and more rapid," Sass said.
"I expect by 2100, we will be seeing 5 to 8 degrees Celsius change in the average temperature of the Earth," he said.
Sass believed the accelerating pace of global warming combined with a cyclic, periodical oscillation of temperatures led to this year's stifling heat. But the former outweighs the latter.
"There is natural variation in weather obviously that we experience periodically, but the gradual increase of the climate temperature changes the precipitation all caused by the emission of greenhouse gases to the atmosphere," he said.
So far as the United States is concerned, the most hit place by the summer heat is its southwest. The states of Texas, Oklahoma and New Mexico not only saw heat but also droughts.
Sass said 2013 was possibly not the hottest in recent years.
"I would say 2011 was just as warm, or maybe warmer than this year. 2013 is probably going to end up warmer. But, over the last 10 years, at least eight of those were very warm years. It has the natural variation of weather, so you might have a cold year coming. You might get another warm year, but in general there will be a trending up towards more and more heat," he said.
Houston, the largest city of Texas notorious for its long and muggy summer, issued a heat advisory early this month as temperature soared above 43 degrees Celsius. Thousands of miles away, in Shanghai, Houston's most known Chinese celebrity Yao Ming 's hometown, the temperature alert was upgraded from orange to red, the highest class.
All across China, 13 provincial-level areas were swept by the extreme heat, leaving about 5.95 million people and 1.72 million heads of livestock short of drinking water, China's Ministry of Civil Affairs said.
Sass, who has been lived in China for a short while for research, said China was susceptible to such extreme weather as its huge agriculture could be affected.
He said, "We have secondary problems caused by extreme weather conditions. We are going to start worrying about plants. I have tried to grow rice plants in 45 degrees Celsius. It won't grow. I would also expect that we will see an increasing rate of malaria and other mosquito-borne diseases. So I would put agriculture and public health at great risk."
Extreme heat does not necessarily come with extreme coldness, Sass said when asked if there is any likelihood of a extreme cold winter this year. In contrary, we may see more and more warm winters.
He said,"While looking at the warm-cold situation, it is to look and see how many records are broken each year. If the climate is normal, the numbers of cold weather records that are broken and the number of warm weather records that are broken should be about the same."
"So far, the number of warm records that have been broken has began to increase and the number of cold weather records that are broken began to decrease. Last year, the number of warm records broken was about 95 percent of the total. We have seen less and less cold weather and we will continue to see less and less cold weather," he added.
To tackle extreme weather, Sass said, the ultimate solution is to reduce green house gas emission by lessening our dependence on fossil-based energy and developing green energy like solar and wind power.
"The best we can do is to mitigate. And the best mitigation we can do is probably, slowly but continuously, changing our energy shift from fossil fuels to alternative resources which don't generate carbon-dioxide," he said.
Sass didn't believe the U.S. government's efforts in reducing carbon emissions were adequate.
"Northern Europe has done probably the best job than anybody in the world in lowering carbon-dioxide output. But the United States, as far as I can see, hasn't done the really necessary things to decrease the carbon-dioxide concentration in the atmosphere," he said.
The Obama administration has pledged that the United States would cut emissions by 17 percent by 2020 from the 2005 levels, and according to data released by the country's Environmental Protection Agency (EPA) in April, emissions fell 6.9 percent from 2005 to 2011.
But for most countries, the year of 1990, rather than 2005, is the base year. Compared with that of 1990, U.S. emissions were up about 8 percent, the data showed.
