Washington: The US might experience an increase of 10 degrees Fahrenheit by the end of the century if steps to address the climate change issue across the globe are not taken, an American draft report has warned.
Noting that evidence for climate change abounds, from the top of the atmosphere to the depths of the oceans, the draft of the third National Climate Assessment, released yesterday said that there is "unambiguous evidence" that planet earth is warming.
"Climate change is already affecting the American people. Certain types of weather events have become more frequent and/or intense, including heat waves, heavy downpours, and, in some regions, floods and droughts," the report said.
"Sea level is rising, oceans are becoming more acidic, and glaciers and arctic sea ice are melting. These changes are part of the pattern of global climate change, which is primarily driven by human activity," it said.
"The amount of warming by the end of the century is projected to correspond closely to the cumulative global emissions of greenhouse gases up to that time: roughly 3 degrees Fahrenheit to 5 degrees Fahrenheit under a lower emissions scenario involving substantial reductions in emissions after 2050 (referred to as the "B1 scenario"), and 5 degrees Fahrenheit to 10 degrees Fahrenheit for a higher emissions scenario assuming continued increases in emissions (referred to as the "A2 scenario")," the draft of the National Climate Assessment warned.
Observing many impacts associated with these changes are important to Americans` health and livelihoods and the ecosystems that sustain, the report said, while some changes will bring potential benefits, such as longer growing seasons, many will be disruptive to society because the institutions and infrastructure have been designed for the relatively stable climate of the past and not the changing one of the present and future.
The draft report, which was made public for the people and experts to respond, said that the average US temperature has increased by about 1.5 degrees Fahrenheit since 1895; more than 80 per cent of this increase has occurred since 1980.
The most recent decade was the nation`s hottest on record.
"US temperatures will continue to rise, with the next few decades projected to see another 2 degrees Fahrenheit to 4 degrees Fahrenheit of warming in most areas," the report said.
The chances of record-breaking high temperature extremes will continue to increase as the climate continues to change, the report said, adding that there has been an increasing trend in persistently high night time temperatures, which have widespread impacts because people and livestock get no respite from the heat.
"In other places, prolonged periods of record high temperatures associated with droughts contribute to conditions that are driving larger and more frequent wildfires," the report said.
"There is strong evidence to indicate that human influence on the climate has already roughly doubled the probability of extreme heat events like the record-breaking summer of 2011 in Texas and Oklahoma," it added.