Thanks to climate change, 80 per cent of people living in America have been experiencing pleasant and favourable weather conditions during the last 40 years — winter throughout the U.S. has become warmer with increasing temperatures but summer temperature has not risen to levels where it has become markedly uncomfortable. The result is that weather has shifted toward a temperate year-round climate that Americans have been demonstrated to prefer.
There has been a steep rise in January maximum temperatures — an increase of 0.58 degree C per decade. But daily maximum temperatures in July increased very slightly by 0.07 degree C per decade. Moreover, humidity in the summer has declined somewhat since the mid-1990s. In other words, winter temperatures have become warmer for virtually all Americans while summer conditions have remained relatively constant.
The results are published today (April 21) in the journal Nature.
A body of evidence shows how climate change might have catastrophic global consequences. And it is true that there has been a rise in the frequency of extreme heat events and a decrease in cold spells in the U.S. and the patterns in these trends vary across regions within the country as well as across seasons. But over all, there has been an improvement in the local weather over the last few decades.
As a result of the favourable weather, there has been “low levels of concern” about the problems of climate change in the U.S. and not sufficient reasons to provoke the public to quickly move to a low-carbon emitting country.
What is indeed worse is that the favourable changes in weather come despite the country being one of the biggest emitters of greenhouse gases. Countries in the tropics, which have not been the biggest emitters of greenhouse gases, have been facing the brunt of climate change such as drought, heat waves, flooding and changed rainfall pattern.
However, favourable weather will not be permanent in the U.S. Long-term projections of temperature changes indicate that weather would become “less” preferable at the end of the 21st Century.
Patrick J. Egan, first author of the study from New York University, New York, estimated “U.S. public’s weather preferences by using an index score that measures the extent to which U.S. migration patterns are associated with weather at different locations, adjusting for confounding factors using a previously reported method”.
In an accompanying News piece, Joacim Rocklöv from the Umeå Center for Global Health Research, Umeå University, Sweden says that the study will be relevant to the attitude of people living in other countries and regions. “In colder regions, such as in Canada, Russia and China, future winter warming may also be perceived as a benefit of climate change, but the weather preference index would need to consider the effects of climate change on snow fall and ice formation, and how people respond to those changes,” he writes.
Rocklöv also points out that 40 years is a relatively short period by the standards of climate change. “Over such short periods, naturally occurring climate variability can confuse the climate-change signal,” and there is no way of differentiating local warming caused by urbanisation with global climate change.
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