We need to stay below 2°C
We are actually very close to tipping points in the world’s climate system. Once a tipping point has been reached a feedback process takes over and it would be nearly impossible to slow it down. Scientists believe that such tipping points could be for example the physical break up of landbound Greenland, the massive release of methane trapped in the permafrost, the die-back of the Amazon rainforest from heat, drought, and fires. the slowing down of the Northern Atlantic circulation etc.
To avoid these tipping points that will cause dangerous and irreversible climate change, the IPCC says that the rise in global average temperature should not be more than 2°C (3.4°F) warmer than it was in pre-industrial times (around 1800).It has already been shown that a rise of 2°C would bring with it a set of devastating impacts to coral reefs, Arctic systems and local communities. The Earth cannot afford to go above this....and this means rapidly cutting greenhouse gas emissions far below current levels. We must start reducing emissions now and stay on a low emissions track to avoid loading the atmosphere with too much CO2. In scientific terms this means staying well below a CO2 concentration level of 450ppm (parts per million) in the atmosphere.
