Humans have enjoyed 10,000 years of climate stability, in which the global average temperature varied less than one degree C – even during the Little Ice Age.
This heating will be wildly uneven with the Arctic warming 2-3 times faster. In 1.5C world much of the far north will be 4.0C. Canada is already 1.6 to 1.8 C warmer today.
Large parts of Africa including the African Sahel, including the Horn of Africa, are very vulnerable to any increase in temperatures. Even with 1.5C large portions of the Arctic and Antarctic will continue to melt raising sea levels, albeit at a slower rate threatening the very existence of some small islands states.
Delay in making the shift to non-fossil fuel energy sources will be very costly. Waiting until 2020 to curb global emissions will cost twice as much compared with peaking emissions by 2015 various analysis have shown.
There are enormous benefits if global emissions decline before 2020. Failure to do so will mean we will need to use more nuclear, massive amounts of bioenergy, large-scale carbon capture and storage
- Joeri Rogelj, a climate scientist at Switzerland’s Institute for Atmospheric and Climate Science