Human activity responsible for 1.5C global temperature rise in last 250 years
The temperature of earth’s land has increased by 1.5C in the last 250 years, and “humans are almost entirely the cause”, a scientific study has concluded.
The report, conducted to address sceptics’ concerns over the role played by humans in climate change, found that that most of this rise had happened in the last 50 years.
“Our results show that the average temperature of the Earth’s land has risen by 2.5F over the past 250 years, including an increase of 1.5 degrees over the most recent 50 years,” wrote Professor Richard Muller, physicist and founder of the Berkeley Earth Surface Temperature (Best) programme, in the New York Times. “Moreover, it appears likely that essentially all of this increase results from the human emission of greenhouse gases.”
Muller, formerly a climate change sceptic, claimed that the results of the study had come as a surprise.
“We were not expecting this, but as scientists, it is our duty to let the evidence change our minds,” he said, adding that his opinions had undergone a “total turnaround” and that he now considered himself a “converted sceptic”.
The study, carried out at the University of California, Berkeley, assimilated 14.4m land temperature observations from almost 45,000 sites across the world, dating back to 1753. Previous experiments, including those by NASA and the Met Office, had drawn data beginning from only the mid-19th century, and gathered only a fraction of the amount of records.
Muller went on to note that he expected to see earth’s land temperatures rise by a further 1.5C over the next 50 years, and warned that if China continued its current economic growth and coal consumption, such a rise could occur within just 20 years.
“I embarked on this analysis to answer questions that, to my mind, had not been answered,” said Muller. “I hope that the Berkeley Earth analysis will help settle the scientific debate regarding global warming and its human causes. Then comes the difficult part: agreeing across the political and diplomatic spectrum about what can and should be done.”
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