World leaders are meeting in Paris this month in what amounts to a last-ditch effort to avert the worst ravages of climate change. Climatologists now say that the best-case scenario—assuming immediate and dramatic emissions curbs—is that planetary surface temperatures will increase by at least two degrees Celsius in the coming decades.
This may sound like a small uptick, but the implications are profound. Rising temperatures will destroy plant and animal habitats, and reduce yields of important food crops. More people will be exposed to the ravages of flooding and drought.
But if the nations involved in the Paris talks stay on their current emissions track and don’t reduce greenhouse-gas emissions, temperatures could go up by almost six degrees Celsius this century, according to the Committee on Climate Change, an independent body that advises the U.K. government on climate issues.
The consequences of a heating globe are already being felt in Alaska, which is warming twice as fast as the rest of the U.S. Rising temperatures have thawed frozen soil in some areas, leaving coastlines vulnerable to storms and tidal activity. Shishmaref, a remote village that sits on an island 30 miles outside the Arctic circle, is losing as many as nine feet of land a year—chunks of coastline that simply break into the sea.
Each year, more species are losing their habitats to climate change. An increase of four degrees Celsius in average planetary temperatures could result in severe habitat loss for almost two-thirds of plant species and one-third of mammal species.
Each year, more species are losing their habitats to climate change. An increase of 4 degrees Celsius in average planetary temperatures could result in severe habitat loss for almost two-thirds of plant species and one-third of mammal species.
Limiting global temperature increases requires reducing carbon emissions. Global fossil fuel and cement consumption are leading drivers of emissions—combined, they’ve risen about 60 percent since 1990. The Global Carbon Project calculates that emissions from these sources will continue to rise.
The green, orange, and yellow lines indicate how surface temperatures will likely respond if leading carbon emitters begin to reduce reliance on fossil fuels. Without immediate curbs, temperatures are set to follow the red track, and increase between 3.2 and 5.4 degrees Celsius by 2100. The green line shows how we can minimize warming if emissions immediately drop—a highly unlikely scenario.