Two degrees may not seem like much, but the implications of our planet growing warmer by just that much are enormous.
“Two degrees is a big deal,” says marine biologist Alan Deidun. “It will have huge impacts, for example, on the melting of the permafrost, the next ‘big thing’ to happen. If the permafrost thaws, it will release even more greenhouse gases into the atmosphere, creating a vicious cycle.”
World leaders meet in Paris this week with the ambitious goal of limiting the global temperature rise to two degrees over pre-industrial levels.
Most scientists agree that increase is already almost inevitable, even if major carbon emitters immediately decrease their output. If emissions were to continue at the current rate, temperatures could rise by as much as 5.4 degrees by 2100, according to data from the Global Carbon Project. Even with a dramatic reduction in fossil fuel reliance, the forecast is still of an increase of 1.7 to 3.7 degrees.
That difference is significant. With an increase of two degrees, for example, the Committee on Climate Change estimates that two million people every year will be exposed to coastal flooding worldwide. But if temperatures increase by four degrees, that figure rises to 13 million.
If the air becomes warmer on a longer scale, Malta will bear the brunt
“If the earth were an apple, the whole atmosphere would only be as thick as the red skin,” says climatologist James Ciarlò. “It’s an extremely fragile system where the slightest temperature change can cause large effects.”
Mr Ciarlò, whose research involves mapping the effects of climate change in the Mediterranean, explains that the region is particularly climate-sensitive.
“In summer, we see a lot of persistent high-pressure systems, which gives us that stagnant air, resulting in heat waves,” he says. “If the air becomes warmer on a longer scale, the fact that it’s stagnant is going to make the situation worse; Malta, since it’s in the middle, is going to bear the brunt.”
The potential effects, by now, are well known. Scientific models predict that prolonged drought, heat waves and torrential rains will all increase in frequency.
These effects are already being seen: the hurricane-like storms Malta witnessed last year were first observed only in the 1990s, Mr Ciarlò explains, and have since gone from occurring once every five years to every year.
Rising sea levels are another pressing concern. The UN’s scientific climate body forecasts rises of approximately 40 to 60 centimetres by 2100, assuming a two degree temperature increase. Different warming scenarios, however, could lead to rises of up to 1.2 metres in the same period. A rise of 50 centimetres would be enough to submerge low-lying areas around Malta and Gozo.
“With the computing power available, climate scientists have more confidence than ever on projections for the years ahead under a number of different scenarios,” says Charles Galdies, a lecturer at the Institute of Earth Systems.
“We have a very good idea what will happen if we cut down on emissions, or if we lose all this impetus and continue to emit at current rates.”