Lethal Heating: 11/29/19

29/11/2019

UNEP Says Global Emissions Must Be Cut By 7.6% Every Year For Next Decade

RenewEconomy - Joshua S Hill

The United Nations Environmental Programme (UNEP) has warned global greenhouse gas emissions must fall by at least 7.6% each year over the next decade or risk missing the 1.5°C temperature goal of the Paris Agreement.
The UNEP’s Emissions Gap Report also highlights seven G20 member nations that are falling well behind their Paris Agreement commitments, including Australia, Japan, South Korea, and the United States.
The UNEP’s annual Emissions Gap Report compares current greenhouse gas emissions against where emissions need to be and where they are heading.
The latest 2019 report shows that things are not going well, and that even if all current unconditional commitments under the Paris Agreement are implemented, temperatures are expected to rise by 3.2°C. Such a dramatic rise in temperature by the end of the century will result in wider-ranging and more destructive climate impacts across the planet.
“For ten years, the Emissions Gap Report has been sounding the alarm – and for ten years, the world has only increased its emissions,” said UN Secretary-General António Guterres. “
There has never been a more important time to listen to the science. Failure to heed these warnings and take drastic action to reverse emissions means we will continue to witness deadly and catastrophic heatwaves, storms and pollution.”

“Our collective failure to act early and hard on climate change means we now must deliver deep cuts to emissions – over 7 per cent each year, if we break it down evenly over the next decade,” added Inger Andersen, UNEP’s Executive Director.
“This shows that countries simply cannot wait until the end of 2020, when new climate commitments are due, to step up action. They – and every city, region, business and individual – need to act now.”
“We need quick wins to reduce emissions as much as possible in 2020, then stronger Nationally Determined Contributions to kick-start the major transformations of economies and societies. We need to catch up on the years in which we procrastinated,” she added. “If we don’t do this, the 1.5°C goal will be out of reach before 2030.”
The report unsurprisingly highlighted the role of G20 member nations, which together account for 78% of global greenhouse gas emissions, and which are “collectively” on track to meet their limited 2020 Cancun Pledges.
However, seven countries – Australia, Brazil, Canada, Japan, South Korea, South Africa, and the United States – are currently not on track to meet their 2030 nationally determined contributions (NDC) commitments, and it is “not possible to say” for a further three countries.
Further, and to make matters worse, six countries – Canada, Indonesia, Mexico, South Korea, South Africa, the United States – are currently on track to miss their Cancun Pledges, while Argentina, Saudi Arabia, and Turkey have not made any 2020 pledges.
In all, only five G20 member nations have committed to a long-term zero emissions target.
The report notes Australia is proposing to “carry forward their overachievement from the Kyoto period to meet their 2020 Cancun Pledges” thanks in part to the Government’s decision to count cumulative emissions between 2013 and 2020.
It notes that if this “carry-forward” approach is not taken, Australia will not even achieve its 2020 pledge.
The authors of the report specify that “it appears that the Australian Government intends to use carry-over permits from the Kyoto Protocol to do so, and uses a carbon budget approach that accounts for cumulative emissions between 2021 and 2030 in order to assess progress against its NDC.”
Australia is also one of the seven countries deemed as requiring “further action of varying degree to achieve their NDC” – a fact not helped by “the re-election of Australia’s conservative Government in May” which has cemented the fact “there has been no recent material change in Australian climate policy.”
“The dropping of the proposed National Energy Guarantee in 2018 and that the renewable energy target will not be raised for years after 2020 up to 2030 … leaves Australia with no major policy tool to encourage emission reductions from the electricity sector in the short to medium term,” write the authors of the UNEP Gap report.
Looking at the overall picture, the UNEP shows that, in the short-term, developed countries will have to reduce their emissions faster than developing countries – a crucial point which will serve to undermine or clash with many conservative talking points around the world.
But the report also says that all nations must substantially increase ambition in their NDCs in 2020 and follow up with ambitious and long-term policies and strategies to implement them.

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'Dangerously Close': Tipping Points May Trigger Climate Cascade

Sydney Morning Herald - Peter Hannam

The planet faces a "global cascade of tipping points" that could lead to an abrupt shift to a warmer world and cause huge disruption to human societies and ecosystems unless nations slash their greenhouse gas emissions.
The warning is contained in an article appearing on Thursday in Nature. The authors identified several "large-scale discontinuities" in the climate system that may be underway, and which could trigger further warming.

Countries need to cut their greenhouse gas emissions much faster than agreed under the Paris Climate Agreement, the UN has warned, or risk "wide-ranging and destructive climate impacts."

Countries need to cut their greenhouse gas emissions much faster than agreed under the Paris Climate Agreement, the UN has warned, or risk "wide-ranging and destructive climate impacts."
"If damaging tipping cascades can occur and a global tipping point cannot be ruled out, then this is an existential threat to civilisation," the scientists said.
The ice sheets in West Antarctica may be one of several cryosphere tipping points that were "dangerously close", if they hadn't already begun an irreversible retreat. These alone would raise sea levels by three metres if melted.

Active global warming tipping points
Evidence that tipping points are under way has mounted in the past decade.

Source: Nature

Illustration: Matt Golding

Those in the Wilkes Basin of eastern Antarctica may be similarly unstable, with another four metres of potential sea-level rise if they disintegrated.
"The time to act decisively is now. Any more dithering is irresponsible, as the risks are increasing year by year," said Stefan Rahmstorf, head of Earth system analysis at Germany's Potsdam Institute for Climate Impact Research, and one of the authors.
"But even once we pass a tipping point – and probably we have done so for the West Antarctic Ice Sheet – we will need to reduce emissions even more urgently, to slow down the unfolding effects and to avoid passing further tipping points."

Running AMOC
The interconnected nature of the giant mixing processes that distribute heat around the world's oceans is a key reason why one region's changes could reinforce other shifts.
For instance, the melting of Greenland's ice sheets is driving an influx of fresh water into the North Atlantic, slowing the Gulf Stream – also known as the Atlantic Meridional Overturning Circulation (AMOC) – by 15 per cent since the middle of the 20th century.
Another outcome is a further heating of the Southern Ocean, resulting in more Antarctic ice melt.

A view from a NASA aircraft of large icebergs that have broken from the calving side of Thwaites Glacier in Antarctica. Credit: NASA

Other effects include drought for the Sahel region because of disruptions to the West African monsoon, and worse fires in the Amazon as that region dries out.
Will Steffen, an emeritus professor at the Australian National University and another author, said some of the processes would add to warming by releasing more carbon dioxide or methane to the atmosphere.
Amazon dieback alone had the potential to release about 90 billion tonnes of CO2 while boreal forests could add another 110 billion tonnes. Even without including the methane, emissions from melting permafrost could total 100 billion more tonnes of CO2, the report said.

Fires in the northern hemisphere's boreal forest will add to the atmosphere's carbon dioxide emissions. Credit: Jason Franson/The Canadian Press

By contrast, humans directly contribute to about 40 billion tonnes of CO2 a year. We also have a total emissions budget of 500 billion tonnes if the world is to have a 50:50 chance of hitting the Paris climate target of keeping warming to 1.5 degrees.
Entire ecosystems, such as the Great Barrier Reef, were also facing tipping points. Half the reef's coral cover had been lost in recent bleaching and only a tiny fraction would remain if warming reached 2 degrees, the paper said.

A red sun among heavy smoke caused by the fires in the Amazon forest in the state of Rondonia, Brazil, in August 2019. Credit: Joedson Alves

Australia is among the most exposed nations given it is already exposed to droughts and heatwaves.
"The warning signs are clear," Professor Steffen said. "It will be a much tougher climate for us to live in."

Mustering of sheep in a paddock of a failed wheat crop at Rebecca and Dan Reardon's property near Moree, NSW, which has been affected by years of drought. Credit: Alex Ellinghausen

The risk was not of runaway global warming but rather of a world stabilising at perhaps 5 degrees warmer.
"The schoolchildren are right," he said. "We indeed have a climate emergency, and an emergency-level response is now needed to ensure that we don’t activate the tipping cascade."

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Climate Emergency: World 'May Have Crossed Tipping Points’

The Guardian - Damian Carrington

Warning of ‘existential threat to civilisation’ as impacts lead to cascade of unstoppable events

‘Part of the west Antarctic ice sheet may be in irreversible retreat,’ said one of the researchers. Photograph: Handout/AFP/Getty Images

The world may already have crossed a series of climate tipping points, according to a stark warning from scientists. This risk is “an existential threat to civilisation”, they say, meaning “we are in a state of planetary emergency”.
Tipping points are reached when particular impacts of global heating become unstoppable, such as the runaway loss of ice sheets or forests. In the past, extreme heating of 5C was thought necessary to pass tipping points, but the latest evidence suggests this could happen between 1C and 2C.
The planet has already heated by 1C and the temperature is certain to rise further, due to past emissions and because greenhouse gas levels are still rising. The scientists further warn that one tipping point, such as the release of methane from thawing permafrost, may fuel others, leading to a cascade.
The researchers, writing in a commentary article in the journal Nature, acknowledge that the complex science of tipping points means great uncertainty remains. But they say the potential damage from the tipping points is so big and the time to act so short, that “to err on the side of danger is not a responsible option”. They call for urgent international action.
“A saving grace is that the rate at which damage accumulates from tipping could still be under our control to some extent,” they write. “The stability and resilience of our planet is in peril. International action – not just words – must reflect this.”

Scientists' warning: a cascade of climate tipping points is possible

Guardian graphic. Source: Lenton et al, Nature, 2019

Prof Tim Lenton at the University of Exeter, the lead author of the article, said: “We might already have crossed the threshold for a cascade of interrelated tipping points. The simple version is the schoolkids [striking for climate action] are right: we are seeing potentially irreversible changes in the climate system under way, or very close.”
“As a scientist, I just want to tell it how it is,” he said. “It is not trying to be alarmist, but trying to treat the whole climate change problem as a risk management problem. It is what I consider the common sense way.”
Phil Williamson at the University of East Anglia, who did not contribute to the article, said: “The prognosis by Tim Lenton and colleagues is, unfortunately, fully plausible: that we might have already lost control of the Earth’s climate.”
The new article comes as the UN warns action is very far from stopping global temperature rise, with the world currently on track for 3C-4C. The commentary lists nine tipping points that may have been activated.

The scientists report that 17% of the Amazon rainforest has been lost since 1970. Photograph: Léo Corrêa/AP

“We have this alarming evidence that part of the west Antarctic ice sheet may be in irreversible retreat,” said Lenton. “All the signals are that it is.” A similar situation appears to be occurring at the Wilkes basin in east Antarctica. The collapse of these ice sheets would eventually raise sea level by many metres.
The massive Greenland ice sheet was melting at an accelerating rate, the scientists said, while Arctic sea ice is shrinking fast. “Permafrost across the Arctic is beginning to irreversibly thaw and release carbon dioxide and methane,” they said.
The Gulf Stream current in the Atlantic, which warms Europe, has also slowed by 15% since the mid-20th century. “That is just about in the range of natural variability, but it is also hard to rule out that it is part of a longer downturn,” Lenton said.
The scientists report that 17% of the Amazon rainforest has been lost since 1970. The tipping point, where loss of forest leads to it drying out, could lie in the range 20%-40%, they said. In temperate forests, especially in North America, heating has triggered more fires and pest outbreaks, potentially turning some regions from a sink for carbon to a source. In the tropics, corals are predicted to be wiped out by 2C of heating.
A cascade of tipping points could occur because, for example, the melting of Arctic sea ice amplifies heating by exposing dark ocean that absorbs more sunlight. That may increase the melting of Greenland ice and permafrost areas. “Multiple risks can interact, with one change reinforcing another, and with warming of just a degree or two sufficient to result in dramatic cascading effects,” said Williamson.
Prof Martin Siegert, at Imperial College London, said: “The new work is valuable. They are being a little speculative, but maybe you need to be.” He pointed out that the extremely rapid rate at which CO2 was being pumped into the atmosphere was unlikely to have ever occurred on Earth before. “It may mean that tipping points can occur in unexpected ways as there is no geological precedent for this rate of CO2 change.”
The article reports that preliminary results from the latest climate models suggest global heating will be greater than expected, increasing the risk of tipping points. Prof Piers Forster, at the University of Leeds, disagreed on that point. However, he added: “I completely endorse their call for action. Although possibly low probability, the risks they identify are real.”
Lenton said action would still have real benefits, by slowing the impacts and giving more time for people to adapt. He said: “This article is not meant to be a counsel of despair. If we want to avoid the worst of these bad climate tipping points, we need to activate some positive social and economic tipping points [such as renewable energy] towards what should ultimately be a happier, flourishing, sustainable future for the generations to come.”

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