One of the biggest surprises leading up to the 2015 worldwide Paris Agreement on climate-changing emissions was an argument about a new goal. Most argument since has centered on the fact that our actions haven't been sufficient to reach that goal. As it stands, only a handful of nations are even on track to hit their Paris benchmarks. That is now 1.5 degrees.
"E$3 ven with erroneous attribution of extreme weather/climate events and projections using climate models that are running too hot and not fit for goal of projecting 21st century climate change, the IPCC still has not made a strong case for this massive investment to prevent 1.5C warming", she said on her Climate Etc. blog.
The IPCC report was released just as this year's Nobel Prize for Economics was awarded to two professors studying the economic impact of climate change.
Households may face higher energy bills under proposals being considered by the government to meet a far tougher greenhouse gas emissions reduction target. But when you put numbers on these things, some effects are particularly notable, and the roadmap to emissions cuts becomes crystal clear.
"The next few years are probably the most important in our history", she added.
At current levels of greenhouse gas emissions, earth could pass the 1.5 C marker as early as 2030, and no later than mid-century, the Intergovernmental Panel for Climate Change reports with "high confidence"..
Global leaders and climate activists have held up the dire consequences of climate change for decades, with many businesses more recently joining the refrain. A limited rise would give people across the globe and ecosystems across the planet a measure of breathing room, facing a planet with worse weather and climate than from pre-industrial days but one still hospitable to thriving human life. Ecosystems, too, would benefit greatly from limiting warming. Of the more than 100,000 terrestrial species that have been studied, for example, the number expected to disappear from half their range doubles between 1.5 and 2.0°C. Keeping the rise in temperature to 1.5C would mean sea levels by 2100 would be 10cm lower than if the warming was 2C, the likelihood of an Arctic Ocean free of sea ice in summer would be once a century rather than at least once a decade, and coral reefs would decline by between 70 and 90 percent instead of being virtually wiped out.
By 2100, global mean sea level rise is projected to be around 0.1 metre lower. Among them, sea level rises would be around 48cm if the temperature was 1.5C and 56cm for 2C.
A large increase in the use of nuclear power would help keep global warming to below 1.5 degrees, according to a United Nations report published today. Technologically, economically, and politically the challenge is huge, "indicative both of the scale of the challenge and the resistance [the effort will] face", notes Shindell, who also contributed to the report. To get there, emissions would have to be cut by 45 per cent from 2010 levels by 2030, with further action required by 2050. By 2050, emissions will need to be reduced by 100 percent.
Still, even in that scenario much of the damage would already have been done.
Achieving a rapid decarbonisation of the electricity sector will require, at first, deploying proven technology, the Association said. Coal would have to be a relic of the past.
Emissions cuts in transport, buildings, industry, power generation and dietary habits such as eating meat will need to take place in a bid to speed up temperature limits. Countries need to undertake massive de-carbonisation while the developed countries must also address consumption in their countries.
The IPCC does not do any of its own research, so the report draws on more than 6,000 research papers to reach its conclusions.
"Limiting warming to 1.5 degrees Celsius is possible within the laws of chemistry and physics but doing so would require unprecedented changes", said Jim Skea, another co-chair at the IPCC and an expert in sustainable energy at the Imperial College of London.
"There were doubts if we would be able to differentiate impacts set at 1.5C and that came so clearly". The report contrasts the impact of 1.5℃ and 2℃ warmings, giving information on what would be gained by the extra effort needed to limit warming to 1.5℃. Now we find out whether governments will do anything with that knowledge.