Global Warming of 1.5 Degrees Celsius

A special report from IPCC addresses questions raised by the Paris Agreement. The limit on warming is still possible, but will require tremendous effort.

Pathways limiting global warming to 1.5°C with no or limited overshoot would require rapid and far-reaching transitions in energy, land, urban and infrastructure (including transport and buildings), and industrial systems (high confidence). These systems transitions are unprecedented in terms of scale, but not necessarily in terms of speed, and imply deep emissions reductions in all sectors, a wide portfolio of mitigation options and a significant upscaling of investments in those options (medium confidence).

The Chair of the Least Developed Countries Group, Gebru Jember Endalew responds:

The science makes clear that there is an urgent need to accelerate the global response to climate change to avoid exceeding the 1.5°C limit. Governments must increase climate action now and submit more ambitious plans for the future. This includes increasing the level of support to developing countries to enable them to develop and lift their people out of poverty without going down a traditional, unsustainable development pathway.

Update (October 10):  Problem solved. Or not.

Update (October 13):  Ed Simon reacts to the special report.

Only capitalism was able to inaugurate a new geological epoch in the Anthropocene; unique is our dominant ideology’s status in being able to obliterate all of humanity. IPCC Co-Chair Debra Roberts said that the report is a “line in the sand and what it says to our species is that this is the moment and we must act now,” but what should disturb us most is the authors’ accurate alarm at the lack of political will to avert catastrophe. In the United States the coal, oil, and gas industries’ obfuscate, high percentages of Americans believe the lie that climate change is a hoax (while record heat affects the Midwest this October), and the ... administration trashes the Paris Accords.

Jon Queally notes that IPCC reports represent a consensus which tends to understate the risk. And Michael Mann elaborates on the future we face.

Update (October 15):  Rob Urie argues climate change is just one facet of the systemic problems caused by capitalism.

Identification of the industrial age— capitalism, as the cause of climate crisis brings with it a host of related revelations. Capitalist wealth becomes a crude measure of its reciprocal in environmental devastation. The relation of wealth to political power makes timely and / or peaceful resolution improbable. Capitalist accumulation will hereafter be a measure of informed socio-pathology. The writing is on the wall. The American political ‘choice’ between the wealthy or their technocratic servants is a formula for environmental annihilation. The system crisis is a metaphor for the political crisis that makes resolution so intractable.

What again is so provocative about the IPCC report— itself considered overly conservative by other climate commenters, is the truncated time horizon before irreversible environmental consequences begin to unfold. The American belief that progress can be accomplished through electoral politics has always rested on deference to a perpetual tomorrow.

Update (October 20):  Elizabeth Kolbert reiterates that the alarms aren't being heard.

Even as the IPCC warned that 1.5 degrees of warming would be calamitous, it also indicated that, for all intents and purposes, such warming has become unavoidable. 

Perhaps the most important takeaway from the report is that every extra half a degree is world-altering. 

Meanwhile, two and a half degrees, three degrees, or even, per the ... Administration, four degrees of warming are all realistic possibilities. ... This disaster is going to be as bad—as very, very bad—as we make it.

Update (November 1):  A paper published in Nature offers a new estimate of the heat content of the oceans. The finding is 60 percent more heat than previously estimated. That means climate change has already had a larger impact than we realized.

Update (November 3):  A group of British scientists are calling for mass civil disobedience to force governments to take action on climate change.

Update (November 13):  Carol Dansereau argues that capitalism cannot solve climate change.

Solutions to global warming are sitting right in front of us, but we can’t implement them. We don’t hold the reins, we lack the money that our labor created, and our jobs are threatened if we challenge the corporations. This insane, unjust set-up has got to go.

Update (November 14):  An error in the Nature ocean heat content study overstated the certainty of their finding. But the fact that the rate of ocean warming is increasing is not disputed.

Update (November 16):  A study published in Geophysical Research Papers finds that the arctic is warmer now than at any time in the past 120,000 years.

Update (January 13, 2019):  A study published in Science finds that ocean temperatures have been increasing faster than previously understood.

Update (February 3, 2019):  Just now coming across this article in the Bulletin of the Atomic Scientists.

Climate report understates threat

[T]he report, dire as it is, misses a key point: Self-reinforcing feedbacks and tipping points—the wildcards of the climate system—could cause the climate to destabilize even further. The report also fails to discuss the five percent risk that even existing levels of climate pollution, if continued unchecked, could lead to runaway warming—the so-called “fat tail” risk. These omissions may mislead world leaders into thinking they have more time to address the climate crisis, when in fact immediate actions are needed. To put it bluntly, there is a significant risk of self-reinforcing climate feedback loops pushing the planet into chaos beyond human control.

Update (July 26, 2019):  Matt McGrath notes that the IPCC reports calls for carbon dioxide emissions to peak by 2020 to maintain the 1.5 degrees Celsius threshold. He quotes Prince Charles:

I am firmly of the view that the next 18 months will decide our ability to keep climate change to survivable levels and to restore nature to the equilibrium we need for our survival.