The Intergovernmental Panel on Climate Change (IPCC) released its preliminary report on the causes and effects of climate change on Monday. The report shows “unequivocally” that human action is the cause of climate change, and that the effects are direr than previously thought.
The IPCC said that limiting global warming to “2ºC will be beyond reach” in the 21st century unless rapid and immediate action is taken to steeply reduce the production of CO2 and other greenhouse gas (GHG) emissions. Without restrictive intervention, or in the worst-case scenario of continued growth in fossil use, the range rises to a disastrous 4ºC and beyond. Irrespective of estimations, the intensity and frequency of severe weather events are predicted to rise across the globe. Projected changes grow worse with every half degree of global warming.
The report also states that many changes are currently “irreversible for centuries to millennia.” Mountain and polar glaciers are going to continue melting, while sea water levels will continue to rise and “remain elevated for centuries” regardless of any action taken today. It is “virtually certain that the Artic will continue to warm,” thus reducing the amount of artic ice and raising global sea levels permanently. Optimistic estimates with positive action place the level between 0.5 and 3.2m; if no action is taken at all that level increases to between 2 to 7m.
Failing to curb GHG emissions increases the likelihood of “once in a decade” weather events according to the report. Hot weather events such as extreme heat waves could grow in frequency to 4.1 times in a ten-year period at 1.5ºC, to 9.4 times at 4ºC. Droughts, which currently occur 1.7 times every ten years, could be experienced up to 4.1 times. Monsoons and other heavy rainfall are, likewise, expected to increase in frequency and severity as temperatures rise. The combination of drying beds and increased rainfall is expected lead to increased flooding in affected regions. The severity of events would be regionally diverse, but would overall have devastating effects on our food supply.
Even more worryingly, under scenarios of increased CO2 emissions, “ocean and land carbon sinks are projected to be less effective at slowing the accumulation of [GHG] in the atmosphere.” This effect is predicted even under very low GHG emission scenarios where we reduce fossil fuel use. GHG emissions would increase exponentially as carbon emissions from drying wetlands, melting permafrost, and forest fires increase in frequency and exacerbate the problem.
There is room for optimism, however. If governments act immediately, the report details, the most severe effects of climate change could be averted or even reversed. The onus is now on governments to act on the information provided in the report in order to stop global warming and reduce the effects of climate change.
