The world is on the brink of failure to keep global warming at a moderate level, and nations will need to take "unprecedented" measures over the next decade to reduce their CO2 emissions. This is the result of a groundbreaking report by the world's leading scientific body to study climate change.
With global emissions showing little signs of slowing down and the United States, the world's second largest CO2 emitter, reversing a series of Obama era climate change measures, the outlook for the most ambitious goals of the Paris Agreement of 2015 is becoming increasingly narrow. Preventing warming by 1.5 degrees Celsius above pre-industrial levels would require a "rapid and far-reaching" transformation of human civilization on a scale never seen before.
"There is no documented historical precedent" for the comprehensive shift to energy, transportation and other systems, which must reach 1.5 degrees Celsius, wrote the United Nations Intergovernmental Panel on Climate Change (IPCC) in a report requested in the 2015 Paris climate.
At the same time, however, the report is received with hope because it confirms that 1.5 C is still possible – for example, if emissions ceased today, the planet would not reach that temperature. It will probably also trigger even greater climate protection by focusing on 1.5 ° instead of 2 ° as a goal that the world must not miss.
Nonetheless, the transformation described in the document raises unavoidable questions about its feasibility.
The document states most clearly that the world's annual carbon dioxide emissions, which currently exceed 40 billion tons per year, would have to fall sharply by 2030, either to keep the globe completely below 1.5 degrees Celsius, or to allow only a short one "Overshoot" at temperatures.
The total emissions reductions over the next decade would probably be more than 1 billion tons per year, larger than the current emissions of all but a few of the largest emitting countries. By 2050, the report calls for a complete or almost complete reduction in coal burning.
"It's like a deafening, penetrating smoke alarm in the kitchen, we need to put out the fire," said Erik Solheim, Executive Director of the United Nations Environment Program. He added that the need to either completely stop emissions by 2050 or find a way to remove as much carbon dioxide from the air as we say there means net zero must be the new global mantra.
The radical transformation would also mean that in a world where more than 2 billion people are left to live by 2050, large areas to produce food must instead be turned into growing trees that store carbon and energy crops.
"Such large-scale transitions pose major challenges to the sustainable management of the various land-based requirements for human settlements, food, cattle feed, fiber, bioenergy, carbon storage, biodiversity and other ecosystem services," the report says.
The document was produced relatively quickly for the consultative IPCC and represents the work of nearly 100 scientists. It went through an elaborate peer review process with tens of thousands of comments. The last 34-page "Policy Makers Summit" was adopted last week in a marathon meeting of scientists and government officials in Incheon, South Korea.
The report says that the world needs to develop large-scale "negative emissions" programs to remove significant amounts of carbon dioxide from the atmosphere. While the basic technologies do not exist widely, a number of scientists have seriously questioned whether we can ascend in the short period of time that is available.
The bottom line, according to Sunday's report, is that the world is unhappy with the goal.
Current promises by countries under the Paris Climate Agreement would lead to a warming of about 3 degrees Celsius by the end of the century, and the Trump administration recently published an analysis assuming about 4 degrees Celsius (7.2 degrees Fahrenheit) 2100, if the world does nothing.
The IPCC is considered to be the authoritative source for climate science, but its conclusions tend to be conservative. That's because it's driven by a consensus process and its results are not just the result of science, but also negotiating with governments about their precise language.
In its Sunday report, the group explained the magnitude and unprecedented nature of the changes needed to keep the warming up to 1.5 degrees Celsius, but she did not stop to consider the feasibility of achieving that goal. (An early draft had stated a "very high risk" for a warming of more than 1.5 ° C, this language is now gone, though the basic message can still be easily deduced.)
"If you expect IPCC to jump up and down and make red flags, you'll be disappointed," said Phil Duffy, president of the Woods Hole Research Center. "They will do what they always do, to publish very cautious reports in extremely dispassionate language."
Some researchers, including Duffy, are skeptical of the scenarios that the IPCC is suggesting that warming will remain at 1.5 ° C, in particular the dependence on negative-emission technologies to keep the window open.
"Even if it is technically possible without reconciling the technical, political and social aspects of feasibility, this will not happen," added Glen Peters, research director of the Center for International Climate Change Research in Oslo. "To limit global warming below 1.5 ° C or 2 ° C, all countries and all sectors must act."
To illustrate the difficulty of interpreting possibilities, the IPCC mentioned in the report two separate figures for the remaining "carbon budget" of the earth or how much carbon dioxide we can emit and still have a chance to stay below 1.5 ° C. The result is we may have either 10 or 14 years of current emissions, and not more if we have a two-thirds or better chance of avoiding 1.5C.
The already limited budget would shrink further if we do not control other greenhouse gases such as methane or if arctic permafrost becomes a major source of new emissions.
Meanwhile, the report clearly documents that warming by 1.5 degrees Celsius would be very damaging and that 2 degrees, which was previously considered a reasonable target, could become unbearable in parts of the world.
"1.5 degrees are the new 2 degrees," said Jennifer Morgan, executive director of Greenpeace International, who was in Incheon, South Korea, for completing the report.
The document notes that "instabilities in Antarctica and Greenland that could induce sea-level rise, measured in feet rather than inches, could be triggered by 1.5 to 2 degrees Celsius of global warming". In addition, the total loss of tropical coral reefs is at stake since 70-90 are expected at 1.5 C, the report said. At 2 degrees, this number rises to more than 99 percent.
The report found that keeping the warming to 1.5 degrees Celsius could save an Alaskan region in the Arctic from permafrost thawing, stopping a feedback loop that could lead to even more global emissions. The occurrence of completely ice-free summers in the Arctic Ocean ranges from one per century to one per decade between 1.5 and 2 degrees, he found – one of many ways in which the mere half-degree has major implications in the real world.
The risks of extreme heat and weather events are rising and rising with temperatures, meaning that the warmer they are the worse around the world.
To avoid this, the global share of renewable energies such as solar and wind energy would have to increase in just over 10 years from the current 24 percent to just over 50 or 60 percent. Coal and gas power plants that remain in operation would need to be equipped with technologies collectively called carbon capture and storage (CCS) that prevent carbon dioxide from being emitted into the air and buried underground instead. By 2050, most coal-fired power plants would be shut down.
Cars and other means of transport would have to move strongly towards electrification, driven by the same renewable energy sources. Transport is far behind the electricity sector when it comes to switching to low-carbon fuels – only 4% of road transport is powered by renewable fuels.
The World Coal Association has challenged the statements in the report on the need to dispose of coal.
"While we're still reviewing the draft, the World Coal Association believes that any credible path to achieving the 1.5 degree scenario needs to focus on emissions rather than fuel," said Katie Warrick, the group's interim CEO Statement. "That's why CCS is so important."
This is an approach that has been largely adopted by the head of the Environmental Protection Agency, who has taken numerous steps under Trump to reverse the rules for the coal industry.
In an interview with the Washington Post last week, Andrew Wheeler, acting administrator of the EPA, said that the United States "will continue to participate in the UN's efforts," although Trump has said that he wants to withdraw from Paris's climate policy as soon as possible legally possible.
But he specifically asked what it would take to keep the world at a dangerous level of climate change. Wheeler declined to set a specific threshold. The regulatory approach of the agency provides that the coal industry "could continue to develop innovations for clean coal technologies and these technologies will be exported to other countries".
Juliet Eilperin of the Washington Post contributed to this report.