15 December 2015, Carbon Brief, The world has spoken. It wants to limit future temperatures rises to 1.5C above historic levels. To achieve this everything must change. The twelfth of December 2015 may well be remembered as the day the human race came together and saved the world. Old differences between rich and poor, west and east were laid aside. Unbeknownst to anyone, six months ago and in secret, the sinking Marshall islanders started to raise an army of more than 100 ambitious nations that rose above the flotsam and jetsam of self-interest and created a stronger climate agreement than anyone thought possible. The Paris agreement aims to hold the increase in the global average temperatures to “well below 2C above pre-industrial levels” and to “pursue efforts to limit the temperature increase to 1.5C”. It also requires parties to produce audited emission-reduction commitments ratcheting up every five years, and delivers a “floor” of $100 billion per year of financing up to 2025. So unexpected was this that we climate scientists were caught napping. Before Paris, we all thought 2C was a near-impossible target and spent our energies researching future worlds where temperatures soared. In fact, there is still much to discover about the specific advantages of limiting warming to 1.5C, and the plausible social and economic pathways that might keep us under this limit. Some have derided the 1.5C target as a pipe dream, given that current national pledges to reduce carbon dioxide emissions – known as Intended Nationally Determined Contributions (INDCs) – could bring us closer to 3C. However, the limited research that does exist suggests that it is possible to overshoot 1.5C and return below it by 2100. And the figure below illustrates how a five-year ratchet mechanism of increasingly ambitious INDCs could deliver a temperature close to 1.5C by 2100. Read More here