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Is Geoengineering the Answer to Limit Global Warming?
By Tim Radford
Geoengineering, the deliberate alteration of the planet to undo its inadvertent alteration by humans over the past 200 years, is back on the scientific agenda, with a climate compromise suggested as a possible solution.
One group wants to turn down the global thermostat and reverse the global warming trend set in train by greenhouse gases released by fossil fuel combustion, by thinning the almost invisible cirrus clouds that trap radiation and keep the planet warm.
Another group proposes to inject sulphur particles into the stratosphere, and keep on doing so for 160 years, to block enough sunlight and lower the planetary temperature.
And a third group wants to see a cocktail of both approaches: thin the high cirrus clouds that stop heat from escaping, and at the same pump particles into the stratosphere to scatter the incoming sunlight and limit the disadvantages of each approach by mixing them.
The verb "wants" in all three studies is neither fair nor appropriate: all three groups concede that the healthy answer is for humans to fulfill the pledge made in 2015, and start to reduce fossil fuel emissions so drastically that global average temperatures stay well below the 2°C maximum rise agreed by 197 nations at the Paris climate conference.
But while most nations have yet to deliver on the plans they have made, and some nations have yet to even devise a plan, and one nation—the U.S.—has announced its withdrawal from the agreement, scientists have been looking for ways to reverse the potentially catastrophic warming and climate change that is now inevitable if the world continues with its "business as usual scenario."
And so, tentatively, and with unpromising conclusions, researchers have looked at ways to alter the planet to protect it from rising temperatures.
They have looked at the northern icepack and wondered if making it whiter would increase solar reflection and slow global warming.
They have repeatedly investigated ways of reducing the incoming sunlight, usually by pumping sulphate aerosols into the atmosphere, and they have even investigated the possibility of making the ocean more thirsty for carbon dioxide, the most problematic greenhouse gas, by pumping iron into the sea to nourish the photosynthesising algae.
And other groups—and sometimes the same groups—have stressed the hazards: while darker skies might reduce hurricane ferocity, such approaches could drastically interfere with rainfall patterns, make life worse for some of the poorest people on Earth and anyway, in the long run, make things hotter.
All in all, the technofix has been pronounced a bad answer to a good question.
But by the end of the century, as sea levels rise by a meter and global average temperatures by 4°C or more, even a bad answer could be the only one on offer. So Ulrike Lohmann and Blaz Gasparini, two scientists from the Swiss Technical Institute known as ETH Zurich, write in the journal Science that the answer might lie in the clouds.
Cirrus clouds in particular don't reflect much sunlight back into space, but because of the altitude and the temperature they do emit less long-wave radiation: they behave, in effect, rather like greenhouse gases.
So if cirrus clouds were carefully created by artificial means at lower altitudes, then perhaps they would trap less heat.
Such an experiment, the scientists concede, could go badly wrong, would not solve problems linked to rainfall patterns and might even make the world warmer. For the moment, they say: "cirrus cloud thinning should be viewed as a thought experiment."
And in the same journal two scientists from the Max Planck Institute for Meteorology in Hamburg, Germany, and the U.S. National Center for Atmospheric Research in Boulder, Colorado, look once again at the stratosphere solution: what sulphur particles could do to cool the planet.
This is an idea already tested naturally. Volcanic eruptions have been linked to planetary cooling, and other groups have even warned that a modest nuclear war could darken the skies and lower global temperatures to potentially lethal levels.
So Ulrike Niemeier and her colleague Simone Tilmes consider what would be necessary if humans wait until 2040 to reduce fossil fuel use and look for effective ways to suck impossible volumes of carbon dioxide out of the atmosphere.
To limit the temperature increase to 2°C above pre-industrial levels, humans would have to pump sulphur into the stratosphere at a cost of $20 billion a year for 160 years, to darken the skies and reduce incoming sunlight.
Such a step, which could slow the water cycle and suppress the Asian monsoons, would not reduce the acidification of the oceans, and could trigger other unwelcome side effects that could lead to global conflicts. So, the scientists say, any such plan would need international agreement and supervision.
And, in the journal Geophysical Research Letters, Chinese, Indian and U.S. researchers arrive at the compromise solution. The dark skies approach could reduce rain too much, thinner cirrus could reduce rain too little.
But computer models suggest that if both methods were deployed carefully and in concert, geoengineers could cool the world but keep the rainfall steady overall.
"The same amount of rain fell around the globe in our models, but it fell in different places, which could create a big mismatch between what our economic infrastructure expects and what it will get," said Ken Caldeira of the Carnegie Institution for Science in the U.S., and one of the authors.
"More complicated geoengineering solutions would likely do a bit better, but the best solution is simply to stop adding greenhouse gases to the atmosphere."
Reposted with permission from our media associate Climate News Network.
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georgeclerk / E+ / Getty Images
By Jennifer Molidor
One million species are at risk of extinction from human activity, warns a recent study by scientists with the United Nations. We need to cut greenhouse gas pollution across all sectors to avoid catastrophic climate change — and we need to do it fast, said the Intergovernmental Panel on Climate Change.
This research should serve as a rallying cry for polluting industries to make major changes now. Yet the agriculture industry continues to lag behind.
"The Ministry of Environment, Natural Resources Conservation and Tourism wishes to inform the public that following extensive consultations with all stakeholders, the Government of Botswana has taken a decision to lift the hunting suspension," the government announced in a press release shared on social media.
Company Safety Data Sheets on New Chemicals Frequently Lack the Worker Protections EPA Claims They Include
By Richard Denison
Readers of this blog know how concerned EDF is over the Trump EPA's approval of many dozens of new chemicals based on its mere "expectation" that workers across supply chains will always employ personal protective equipment (PPE) just because it is recommended in the manufacturer's non-binding safety data sheet (SDS).
By Grant Smith
From 2009 to 2012, Gregory Jaczko was chairman of the Nuclear Regulatory Commission, which approves nuclear power plant designs and sets safety standards for plants. But he now says that nuclear power is too dangerous and expensive — and not part of the answer to the climate crisis.
By Brett Walton
When Greg Wetherbee sat in front of the microscope recently, he was looking for fragments of metals or coal, particles that might indicate the source of airborne nitrogen pollution in Rocky Mountain National Park. What caught his eye, though, were the plastics.
In a big victory for animals, Prada has announced that it's ending its use of fur! It joins Coach, Jean Paul Gaultier, Giorgio Armani, Versace, Ralph Lauren, Vivienne Westwood, Michael Kors, Donna Karan and many others PETA has pushed toward a ban.
This is a victory more than a decade in the making. PETA and our international affiliates have crashed Prada's catwalks with anti-fur signs, held eye-catching demonstrations all around the world, and sent the company loads of information about the fur industry. In 2018, actor and animal rights advocate Pamela Anderson sent a letter on PETA's behalf urging Miuccia Prada to commit to leaving fur out of all future collections, and the iconic designer has finally listened.
If people in three European countries want to fight the climate crisis, they need to chill out more.
"The rapid pace of labour-saving technology brings into focus the possibility of a shorter working week for all, if deployed properly," Autonomy Director Will Stronge said, The Guardian reported. "However, while automation shows that less work is technically possible, the urgent pressures on the environment and on our available carbon budget show that reducing the working week is in fact necessary."
The report found that if the economies of Germany, Sweden and the UK maintain their current levels of carbon intensity and productivity, they would need to switch to a six, 12 and nine hour work week respectively if they wanted keep the rise in global temperatures to the below two degrees Celsius promised by the Paris agreement, The Independent reported.
The study based its conclusions on data from the UN and the OECD (Organisation for Economic Co-operation and Development) on greenhouse gas emissions per industry in all three countries.
The report comes as the group Momentum called on the UK's Labour Party to endorse a four-day work week.
"We welcome this attempt by Autonomy to grapple with the very real changes society will need to make in order to live within the limits of the planet," Emma Williams of the Four Day Week campaign said in a statement reported by The Independent. "In addition to improved well-being, enhanced gender equality and increased productivity, addressing climate change is another compelling reason we should all be working less."
Supporters of the idea linked it to calls in the U.S. and Europe for a Green New Deal that would decarbonize the economy while promoting equality and well-being.
"This new paper from Autonomy is a thought experiment that should give policymakers, activists and campaigners more ballast to make the case that a Green New Deal is absolutely necessary," Common Wealth think tank Director Mat Lawrence told The Independent. "The link between working time and GHG (greenhouse gas) emissions has been proved by a number of studies. Using OECD data and relating it to our carbon budget, Autonomy have taken the step to show what that link means in terms of our working weeks."
Stronge also linked his report to calls for a Green New Deal.
"Becoming a green, sustainable society will require a number of strategies – a shorter working week being just one of them," he said, according to The Guardian. "This paper and the other nascent research in the field should give us plenty of food for thought when we consider how urgent a Green New Deal is and what it should look like."
- Reduced Work Hours as a Means of Slowing Climate Change ›
- How working less could solve all our problems. Really. | ›
- Needed: A shorter work week – People's World ›