Global Temperatures Over Last 24,000 Years Shows Today’s Warming Is “Unprecedented”

The current planetary increase in temperature from human - caused glasshouse gas emissions is the fastest variety to the satellite ’s climate since the peak of the last Ice Age 24,000 years ago . In a new data analysis , researcher reconstructed the variation in temperatures over the last 24 millennia and found current global temperature are " unprecedented " .

The new study , led by the   University of Arizona and print inNature ,   add   to evidence thathuman activityis the cause of the climate crisis . By retrace the Earth ’s mood since the last Ice Age , it highlight the chief drivers of climate change and the stop number this change is fall out .

It show that over the 9,000 years between the early Holocene and the beginning of the Industrial Revolution , the global mean temperature increased by about 0.5 ° degree centigrade ( 0.9 ° F ) . Over the last 150 age , however , the global mean temperature has increasedby over 1.2 ° cytosine ( 2.16 ° F ) . An unbelievable magnitude and upper of variety compare to innate variation .

" This reconstruction suggests that current temperatures are unprecedented in 24,000 age , and also indicate that the upper of homo - caused globose thaw is fast than anything we ’ve seen in that same time , " Colorado - generator Professor Jessica Tierney , who is a contribute writer of the UN’sIPCC reportand brief US Congress on climate issuance , pronounce in astatement .

" The fact that we ’re today so far out of bound of what we might consider normal is cause for alarm and should be surprising to everybody , " contribute lead study author   Dr Matthew Osman .

To study the change since the last glacial maximum , the team combined two independent methods . One is to use maritime sediments . The shells of mollusks can be used as a temperature proxy as temperature change over time bear upon the interpersonal chemistry of their shells . This is not a perfect thermometer but it is a good starting point .

The other method acting is simulated climate models using humans ’s unspoiled understanding of Earth ’s historical clime , which is also limited but by assimilate the data of the two , the team take to tone their finding . They created single-valued function of the entire planet , where temperature alteration can be tracked for the whole 24,000 age in separation of 200 years .

" These maps are really powerful , " Osman said . " With them , it ’s possible for anyone to explore how temperature have commute across Earth , on a very personal level . For me , being capable to envision the 24,000 - twelvemonth evolution of temperatures at the exact locating I ’m sitting today , or where I grew up , really helped ingrain a sense of just how terrible climate change is today . "

The squad is now using this method to see at mood changes that occur even in the first place , to better realise the phylogeny of the satellite ’s climate before we altered it so dramatically .