October 9th, 2018
Perhaps the most surprising thing is how hopeful report is, with the incredibly wordy title of GLOBAL WARMING OF 1.5 °C: an IPCC special report on the impacts of global warming of 1.5 °C above pre-industrial levels and related global greenhouse gas emission pathways, in the context of strengthening the global response to the threat of climate change, sustainable development, and efforts to eradicate poverty. http://report.ipcc.ch/sr15/pdf/sr15_spm_final.pdf.
It all sounds, at worst, survivable. Some samples from the summary are to be found as follows:
B2.1.Model-based projections of global mean sea level rise (relative to 1986-2005) suggest an indicative range of 0.26 to 0.77 m by 2100 for 1.5°C global warming, 0.1 m (0.04-0.16 m) less than for a global warming of 2°C (medium confidence). A reduction of 0.1 m in global sea level rise implies that up to 10 million fewer people would be exposed to related risks, based on population in the year 2010 and assuming no adaptation (medium confidence).
B2.2.Sea level rise will continue beyond 2100 even if global warming is limited to 1.5°C in the 21st century (highconfidence). Marine ice sheet instability in Antarctica and/or irreversible loss of the Greenland ice sheet could result in multi-metre rise in sea level over hundreds to thousands of years. These instabilities could be triggered around 1.5°C to 2°C of global warming
B3.3.High-latitude tundra and boreal forests are particularly at risk of climate change-induced degradation and loss, with woody shrubs already encroaching into the tundra (high confidence) and will proceed with further warming. Limiting global warming to 1.5°C rather than 2°C is projected to prevent the thawing over centuries of a permafrost area in the range of1.5 to 2.5 million km2
B4.1. There is high confidence that the probability of a sea-ice-free Arctic Ocean during summer is substantially lower at global warming of 1.5°C when compared to 2°C. With 1.5°C of global warming, one sea ice-free Arctic summer is projected per century. This likelihood is increased to at least one per decade with 2°C global warming.
The list goes on, and it doesn’t discuss some of the direst scenarios for a world in which the temperatures average 1.5C above levels observed between 1850 and 1900. But I’m going to.
Dr Goodwin and Professor Williams advise that cumulative carbon emissions needed to remain below 195-205 PgC (from the start of 2017) to deliver a likely chance of meeting the 1.5°C warming target while a 2°C warming target requires emissions to remain below 395-455 PgC.
(Philip Goodwin, Anna Katavouta, Vassil M. Roussenov, Gavin L. Foster, Eelco J. Rohling, Richard G. Williams. Pathways to 1.5°C and 2°C warming based on observational and geological constraints. Nature Geoscience, 2018; DOI: 10.1038/s41561-017-0054-8)
Present emissions are around 550 PgC (pettagrams Carbon). We would have to cut those emissions by 20% starting last year to limit warming to 2C, and 60% starting last year to meet a goal of 1.5C.
Not. Going. To. Happen.
We’re already at .87C above preindustrial levels, and of course it varies, sometimes by quite a bit, and in fact in 2015, during a big El Niño event, we already blew past the 1.5C market, hitting 1.58C.
As the chart shows, the most optimistic scenario has us hitting 1.75C before tailing off slowly to 1.5C by the end of the century. If we maintain present emission levels, the chart says we’ll hit 2.0C and just stay there.
The good news is we’re on course to flatten CO2 annual emissions. No matter what the destructive and purblind Trump administration thinks. In fact, they’ve decided we’re already being raped, so we might as well just accept it, with a report the day before the IPCC Special Report stating that a 4C rise was inevitable. The right wing Chicago Tribune reported, “The draft statement, issued by the National Highway Traffic Safety Administration (NHTSA), was written to justify President Donald Trump’s decision to freeze federal fuel efficiency standards for cars and light trucks built after 2020.”
The horrific thing is that Trump could make this happen, in the name of Disaster Capitalism. Your tragedy is their profit.
Four degrees would be utterly catastrophic. At best, millions would die, and since the huge human and economic dislocations would almost certainly trigger global war, the death toll could easily be in the billions.
The IPCC doesn’t discuss knock-on effects of warmer temperatures. In the case of 1.5C, those effects may be somewhat limited, both in terms of ice and permafrost loss and habitat change (perhaps 15% of existing habitat would be subject to major change). At 2.0C they would be much more pronounced, with ice loss driving Arctic temperatures, already 4C above normal, to about 8C above normal. Ice-free summers would become common (IPCC says one per decade, somewhat optimistically.) Melting tundra and muskeg permafrost would release many gigatonnes of CO2, ocean temperatures would change enough to interfere and even stop some of the main current flows, and habitation and bioregional changes would be dramatic and widespread. Tens of millions of people would have to relocate, sparking already inflamed political tensions.
Greenland and Antarctica, already showing melt rates far beyond what anyone expected, would lose their icecaps altogether, in Greenland’s case before the end of the century.
We’re already well behind what is needed to prevent 2.0C, let along 1.5C. Things aren’t as bad as the Trump administration, which in a burst of unequaled cynicism have decided it’s more profitable to just give up now, says, but Trump and his type want it, because authoritarians prefer suppressed populations that are desperate, frightened, and utterly dependent on the authoritarians to save them.
Another thing that’s Not. Going. To. Happen.
If we want to save ourselves, we have to save ourselves. Vote for candidates strong on climate change, and reject the tawdry self-serving cynicism of Trump and his corporate masters. He isn’t going to save you. In fact, he thinks you’re more useful if you’re struggling to survive and begging him for help. And that’s Not. Going. To, Happen, either.
