It is commonly quote that the humankind needs to keep the global temperature below 2 ° century ( 3.6 ° atomic number 9 ) above pre - industrial level . If temperature rise above this , many think it will cause widespread ecologic cataclysm , as ice caps melt , sea levels rise , currents break , and coral reefs decease . Butthere is some debateas to what incisively the “ pre - industrial ” levels should be .
The Paris clime concord , in which all of the world ’s politics came together to jibe to keep worldwide temperature well within the 2 ° nose candy ( 3.6 ° atomic number 9 ) boundary and to strive below 1.5 ° ascorbic acid ( 2.7 ° fluorine ) above pre - industrial temperatures , does n’t actually delimit what this means .
Most researchers take the pre - industrial service line as the average worldwide temperature between 1850 and 1900 , but thisthrows a few problemsinto the premix . By this compass point in time , the Industrial Revolution was already in full baseball swing , with fossil fuels being burn and atomic number 6 emitted as the standard . This fourth dimension period of time also curb some large volcanic eruption , which would skew the information .
This make using the 1850 - 1900 baseline to represent “ pre - industrial ” temperature a little foxy . The writer of a new study , published in theBulletin of the American Meteorological Society , suggest we should really be comparing modern temperatures to those from between 1720 and 1800 , as during this metre the natural condition were similar to how they are now , meaning that any observed differences would be down to human and not pas seul .
Yet this brings up its own exculpated problem . While we can accurately guess the atmospherical condition – such as carbon copy dioxide and methane density – dating back C of chiliad of years by analyse the tiny bubble of aviation trapped in ice , how do we mensurate the temperature ?
Well , it turns out that temperature phonograph record for some places do exist that stretching back this far , in the main from cardinal England , the Netherlands , and Europe . Coupling this with modeling , it can give some denotation as to how temperature have shifted from the 1700s to now . The squad base that during this pre - industrial menstruum up to 1986 - 2005 , global temperature have likely increased by more than 0.6 ° light speed ( 1.08 ° atomic number 9 ) .
It also means that 2015 will have been the first time in recorded chronicle that global temperatures have been higher than 1 ° degree Celsius ( 1.8 ° F ) above pre - industrial levels . These new calculations do have a wider range due to the increased dubiety with sit the temperature from so long ago , but they still show that we are well on our path to smashing that 1.5 ° C ( 2.7 ° degree Fahrenheit ) limit .
Inevitably , many will chastise this as an endeavor to “ shift the goal posts ” , but in world it only mean that policy and targets can be more accurately set and our impact on the environment more accurately evaluate .
