Glaciologists have long feared certain Antarctic Glaciers have “ tipping points ” beyond which their diminution will be almost unsufferable to reverse . Proof in specific cases has been harder , but now one team say they have confirmed thePine Island Glacier , one of the bang-up threats to global ocean spirit level , fit the bill and we are getting scarily close .
Tipping points play perhaps the greatest germ of uncertainness in climate research . Until one is reached , a arrangement may agitate in one centering as the global temperature warms , but can be gestate to reverse if we ever cool down . In some cases , however , once a threshold is crossed , even a hearty fall in temperatures will not restore the late situation .
For sure major small-arm of the clime puzzle , we know there are tipping points , although how near we are to crossing them is usually less sealed . For others , it ’s indecipherable if these thresholds exist at all . Until now , Pine Island Glacier , West Antarctica , has been one of the later , but Northumbria University’sDr Sebastian Rosierclaims to have locate that question . In fact , Rosier argues inThe Cyrosphere , this mighty river of ice has three tipping point , but it is the last one that count .
Whether a glacier has a tipping degree depends on the cast of the terrain on which it sit around . That ’s a challenge to determine since , by definition , the underlying rock is buried beneath vast measure of ice . Even once the contours are known , scientists need to model what will happen as ice retreats , exposing new cloth to saltwater , which causesfresh meltingand a vicious circle .
" Many different computer simulations around the world are set about to quantify how a change mood could strike the West Antarctic Ice Sheet but identifying whether a menstruation of retreat in these model is a tipping point is challenge , ” Rosier say in astatement . " However , it is a crucial question and the methodology we use in this new study makes it much easier to describe potential succeeding tipping points . "
Once pass over , the first two tipping compass point , the paper reports , will cause modest areas of the glacier to melt , even if temperature stop rise . The third , however ; “ guide to a retreat of the entire glacier that could originate a crash of the West Antarctic Ice Sheet . ”
The authors predict this will hap at ocean temperatures around 1.2 ºC ( 2.2 ºF ) warm than initial conditions .
Along with its neighbour theThwaites Glacier , Pine Island is one of Antarctica ’s fastest - move glaciers . The twain ’s speedy thawing account for 10 per centum of global ocean - grade upgrade at the moment – and possibly much more in the time to come . These glacier and the expanse they protect not as large as East Antarctica but are look at much more vulnerable . Since they are well sufficient to overwhelm many of the earth ’s large cities and most populated river deltas , they could make what happen to East Antarctica further into the future almost irrelevant .
