Commonly 2°C has been seen as the threshold for dangerous climate change, although last year the IPCC report on 1.5°C revealed that at that lower level we enter a zone where tipping points may take us to 4°C and beyond.
In 1999 NASA lost its $125-million Mars Climate Orbiter because spacecraft engineers failed to convert from Imperial to metric measurements when exchanging vital data before the craft was launched. Numbers are important!
I’ll come back to that. However, Tamino at Open Mind points out that while the Arctic warms three to four times as fast as global warming, the Arctic winters are warming at a much faster rate.
Using the NASA data, which is about mid-range in the major players, Tamino finds that the overall average warming rate since 1985 in the Arctic, at 6.48°C/century is fully 3.4 times as fast as the global rate since 1985 of 1.90°C/century. Continue reading Trouble at the top of the world→
The target should not be 1.5°C; rather we should aim for a safe climate. James Hansen told us in 2007 that to achieve a safe climate we need to bring GHG concentrations down to 350 ppm as soon as possible. That’s CO2 equivalent, not CO2. Current CO2e is not often quoted, but would be around 500 ppm on the basis that CO2 is about 80% of total GHGs. Also we need to focus on what we are doing to the planet over centuries and millennia, not just the next 50 to 100 years.
However, the IPCC team putting the report together were not asked what the goal should be. They were asked to build a scenario for achieving the 1.5°C warming limit specified as desirable in the Paris Agreement of 2015, and to look at the impacts of a 1.5°C world as against a 2°C world. Two Degrees came out of Europe in the 1990s, achieved a general currency, then became the official goal of at the Conference of Parties of the UNFCCC in Cancun in 2010. At that time there was a move mainly by many of the island states vulnerable it inundation for a more ambitious target. Essentially the whole group at Paris agreed to try.
However, while two degrees was commonly seen as a guardrail for a safe climate even by many scientist, it was never a scientifically derived goal for a safe climate.
Some time in the last few days I heard a person who should know better say that 1800 coal-fired power plants were being built around the world. One wonders where this (dis)information comes from. It went unchallenged by the ABC interviewer, showing once again that ABC journalists and presenters need an update on climate change – in the national interest.
Hansen told the politicians that our production of greenhouse gases, principally CO2, N2O, CH4 and CFC, were warming the climate. He said temperatures would go up in the coming years: Continue reading Hansen got it right→
This assessment involves 84 scientists from more than 40 institutions, and combines data from 24 satellite surveys. It follows in the footsteps of the first IMBIE (Ice Sheet Mass Balance Inter-comparison Exercise) conducted in 2012, and paints a particularly grim picture of the years between then and 2017. Continue reading Antarctic ice loss rates have tripled since 2012→