Half A Degree Separates Us From Catastrophe. This Graphic Breaks It Down — And Makes The Case For Immediate Action.

We still have a chance to stop it, experts say.

The difference between 1.5 degrees Celsius and 2 degrees Celsius may not seem like much, but when it comes to global warming, it could be monumental.

Graphics from the U.K.-based website Carbon Brief show just how drastic that difference might be. If temperature increases hit 2 degrees Celsius by 2100, we'd see more heatwaves, have less fresh water in the Mediterranean and fewer crop yields.

"The rise in temperature that we've seen is very much in line with model predictions," climate scientist Michael E. Mann told A Plus. "At this point, limiting warming to 1.5 degrees Celsius may be very difficult — if not impossible to achieve — but limiting to 2 degrees Celsius is still very much on the table. Though it will require very rapid decarbonization of our economy."

Carbon Brief (www.carbonbrief.org)
Carbon Brief (www.carbonbrief.org)

A 2016 climate change study in Earth System Dynamics sought to specifically examine this difference. Often times, catastrophic climate change is examined by asking what would happen if temperatures rose 4 degrees vs. if they rose 2 degrees Celsius. But this study, and Carbon Brief's coverage of it, shows how a .5 degree Celsius difference could actually be quite significant. These benchmarks are even more pertinent because keeping temperature rise below the 2 and 1.5 degrees Celsius threshold is explicitly mentioned in the Paris Climate Agreement. 

One of the more alarming conclusions of the study is that water shortages in the Mediterranean would nearly double. Wheat and maize production would also plummet, particularly in Africa and South America, and sea level rise would increase 10 centimeters more if temperature increases by 2 degrees Celsius. For low-level island nations already feeling the effects of sea level rise, the difference between a 40-centimeter and 50-centimeter sea level rise cause irreconcilable damage. 

"Too often, tackling climate change is framed as if it is a binary decision, i.e. we avoid catastrophic warming (often defined as 2C relative to pre-industrial), or we don't," Mann said. "The reality is that there is a more continuous scale of damages; 2 degrees Celsius is substantially more dangerous than 1.5 degrees Celsius, 2.5 degrees Celsius is substantially more dangerous than 2 degrees Celsius, etc."

Carbon Brief (www.carbonbrief.org)
Carbon Brief (www.carbonbrief.org)

Perhaps most important, though, is the time we have to stop it. The study suggested that our chances of keeping temperature rise under 1.5 degrees Celsius are already low — and declining by the day. According to an Intergovernmental Panel on Climate Change (IPCC) "budget" for carbon emissions, we can only continue our current emissions for a total of six years if we want at least a 66 percent chance of staying under a 1.5 degrees Celsius increase. The "budget" and the graphic above are two years old, which means we really only have four more years.

As Vox pointed out, "global carbon emissions would need to immediately begin plunging, faster than they ever have, and hit zero by 2050 (and then go negative)" in order for us to hit the breaks in time.

There is still quite a bit of uncertainty around these numbers, though. Much of the carbon budget is based on keeping the earth below "pre-industrial" temperatures, but what exactly those numbers are is still up for debate. Nevertheless, climate scientists around the globe have built consensus around the idea that 2 degrees Celsius is a threshold before things spin out of control. And plenty are doing work to keep temperature rise well below that number. 

Scientists have already laid out a detailed roadmap on how to hit the Paris Climate agreement's goals. It'd require nations to cut carbon emissions by half every decade, and relies on the scaling of technology to remove carbon from the atmosphere. It would also require scrapping more than $500 billion of fossil fuel subsidies across the globe, and phasing out the use of coal in developing nations. We'd have to follow the lead of countries like Denmark, Sweden and Germany and create booming clean energy sectors. By 2050, we'd need almost every European country to be carbon neutral.

Fortunately, some of the work is already underway. Germany is seeing electricity surpluses thanks to their successful renewable energy program. Renewable energy plants are using landfills to capture methane gas. China created a giant panda-shaped solar field, U.S. politicians have floated the idea of a carbon tax and the head of the UN's Food and Agriculture Organization says a low-carbon livestock sector is possible. Meanwhile, a group of American youth, the city of New York and a 9-year-old in India are all suing their respective governments who they believe have enabled carbon emissions that they knew would hurt the environment. If any of those lawsuits are successful, they could force the governments in question to tackle climate change with strict regulation.

Even conservatives in America, one of the few political groups who tend to oppose climate change regulation, are beginning to support the movement to end carbon emissions.

And If the experts are right, we'll need all the help we can get.

(H/T: Vox)


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