If we pass safe climate limits, it’s a long way back

University of Victoria's Andrew MacDougall in Canada's Kluane National Park Credit: Nicolas Roux

University of Victoria’s Andrew MacDougall in Canada’s Kluane National Park Credit: Nicolas Roux

If CO2 levels in the air pass the ‘safe’ limit, we’d have to take out up to four-fifths more than we originally emitted to get back under it. That’s the result from seemingly the first study to look at climate change’s reversibility with plausible scenarios, done by Andrew MacDougall from the University of Victoria (UVic), Canada. “With monumental effort and political will climate change is reversible within the millennium,” Andrew told me. “However, more carbon will need to be extracted from the atmosphere than was originally emitted to it. Meanwhile, changes in sea-level are effectively irreversible on the millennial time-scale.”

Andrew started looking at whether climate change could be undone in autumn 2012, after publishing a study showing that melting permafrost will speed up global warming. “The results were pretty grim,” Andrew said. “Combined with the failure of the political classes to implement controls on carbon emissions I began to wonder if there was a way to undo what humanity will do to the climate if we greatly exceeded the 450 parts per million (ppm) target.” That target comes because scientists say temperatures 2°C higher than the ‘pre-industrial’ average from 1850-1899 could become dangerous, and governments have agreed to keep warming below this level. Scientists also calculate that 450 CO2 molecules are allowable in every million air molecules to give us better than a 3/5 chance of temperature rises below 2°C.

After human emissions cease, current evidence suggests that natural processes would take tens of thousands of years to remove all of the fossil carbon from the atmosphere. Most of the warming will remain, even 10,000 years into the future. This sentence could be reduced by taking CO2 directly from the atmosphere, though this would be a huge effort, on the same scale as today’s fossil fuel industry according to one estimate. One method for doing that involves generating electricity by burning plants or trees that grew by absorbing CO2, and capturing and storing the CO2 from the burning. The other, known as air capture, uses machines to scrub CO2 right out of the air. However, this would need to be powered by clean energy and arguments over its cost are holding back research. Read the rest of this entry »

How ocean data helped reveal the climate beast

Wally Broecker's famous quote on display at California Academy of Sciences.  Image copyright: Jinx McCombs, used via Flickr Creative Commons license

Wally Broecker’s famous quote on display at California Academy of Sciences. Image copyright: Jinx McCombs, used via Flickr Creative Commons license

  • This is part two of a two-part post. Read part one here.

On the wall of Wally Broecker’s building at the Lamont-Doherty Earth Observatory hangs a 16-foot long terry-cloth snake, blue with pink spots, that he calls the ‘climate beast’. Left in his office as a surprise by his workmates, its name refers to one of Wally’s most powerful quotes about the climate: “If you’re living with an angry beast, you shouldn’t poke it with a sharp stick.”

Today, the sharp stick is the CO2 we’re emitting by burning fossil fuels, which Wally was warning about by 1975. By that time he had also helped confirm that throughout history, changes in Earth’s orbit have given the climate beast regular kicks, triggering rapid exits from ice ages. He became obsessed with the idea that climate had changed abruptly in the past, and the idea we could provoke the ‘angry beast’ into doing it again.

Among the many samples that Wally was carbon dating, from the late 1950s onwards he was getting treasure from the oceans. Pouring sulphuric acid into seawater, he could convert dissolved carbonate back into CO2 gas that he could then carbon date. And though nuclear weapon tests had previously messed with Wally’s results, they actually turned out to help improved our knowledge of the oceans. The H-bomb tests produced more of the radioactive carbon-14 his technique counts, and as that spike moved through the oceans, Wally could track how fast they absorbed that CO2.

In the 1970s, as Wally and a large team of other scientists sailed on RV Melville and RV Knorr tracking such chemicals across the planet’s oceans, a debate raged. Was cutting down forests releasing more CO2 than burning fossil fuels? Dave Keeling’s measurements showed the amount of CO2 being added to the air was about half the amount produced by fossil fuels. But plants and the oceans could be taking up huge amounts, scientists argued. Thanks to the H-bomb carbon, Wally’s team found the CO2 going into the oceans was just 1/3 of what fossil fuels had emitted. Faster-growing plants therefore seemed to be balancing out the impact of deforestation, and taking up the remaining 1/6 portion of the fossil fuel emissions. Read the rest of this entry »

Immense energy emissions challenge “not understood”

Carnegie Insititution of Washington's Steven Davis

Carnegie Insititution of Washington’s Steven Davis

Sometimes, climate change seems unstoppable – so much so, it’s tempting to ask: ‘Why bother doing anything about it then?’ Steven Davis of the Carnegie Institution of Washington and his colleagues have provided one answer. They have found that while the power generation facilities and transportation we currently use guarantee some CO2 emissions, those emissions will not themselves reach levels that could cause dangerous climate change.

“The result is hopeful in that what we’ve already built won’t put us over the 2ºC benchmark,” Davis said. A 2°C temperature rise from pre-industrial averages is a stated aim of the Copenhagen Accord, agreed by the world’s countries in December last year. However, Davis warns that taking the right steps to stop emitters yet to be built taking global temperature rises through this limit is a difficult, in fact almost impossible, challenge. “The necessary transition in our energy system is incredibly daunting,” he explains. “The immensity of the challenge is not commonly understood, the political will is lacking, and there are few alternative energy technologies that can attain the required scale.” Read the rest of this entry »

Geo-engineering “quick fix” is a big risk

Beijing Normal University's John Moore, who is also affiliated with the University of Lapland and the University of Oulu in Finland. Credit: Beijing Normal University

Beijing Normal University’s John Moore, who is also affiliated with the University of Lapland and the University of Oulu in Finland. Credit: Beijing Normal University

Climate change is leaving the world’s northernmost inhabitants literally lost for words, according to Beijing Normal University‘s John Moore. “Arctic indigenous people have no local names for bird species migrating into their areas, showing that they have not been seen over the history of their oral tradition,” he explains. Moore also has his own personal connection to the impact of global warming, with ice shelves in Antarctica where he worked in the 1980s having ceased to exist since. Moore expects that further breakup and retreat of ice will follow as temperatures rise. “Dramatic changes are very clearly seen in glaciers in many mountain regions, Greenland’s melting and glacier flow, and the on-going acceleration of glaciers in parts of West Antarctica,” he says.

While these likely impacts are clear, other future happenings are not. “We have been doing a CO2 experiment for centuries and we are still not sure of all the detailed impacts,” Moore says. We know less still about a group of suggested methods for tackling climate change without reducing greenhouse gas emissions, together known as geo-engineering, making using them a potentially high-risk strategy, Moore notes. “Modifying the climate is bound to be risky since every living thing depends on it,” he says. “Human civilization is about as old as the stable climate period of the Holocene,” Moore says. “We know that over the previous 100,000 years climate was very unstable compared with this period. It seems civilization’s origins relied on a stable climate – cities dependent on agriculture would have been unsustainable in a variable climate.” However, geo-engineering could help keep the climate stable while we reduce our greenhouse gas emissions, he adds. “There may be real benefits in helping to get us over the fossil fuel dependency and on to a more sustainable track.” Read the rest of this entry »

Fighting sea rise with mirrors and mock volcanoes

To fight sea level rise it might take pumping suphur dioxide emissions into the atmosphere equivalent to 1991's Mount Pinatubo eruption (shown here) every 18 months. Credit: USGS/Cascades Volcano Observatory

To fight sea level rise it might take pumping suphur dioxide emissions into the atmosphere equivalent to 1991's Mount Pinatubo eruption (shown here) every 18 months. Credit: USGS/Cascades Volcano Observatory

If CO2 emissions can’t be cut, simulating volcanoes could help the 150 million people across the world threatened by rising sea levels, scientists said this week. But the UK, Denmark and China-based researchers who reach these conclusions also warn such ‘geo-engineering’ measures could be dangerous in other ways. “Substituting geo-engineering for greenhouse gas emission control would be to burden future generations with enormous risk,” said Svetlana Jevrejeva of the UK’s National Oceanography Centre.

150 million people worldwide are thought to live within 1 metre of high tide, Jevrejeva’s team notes. In 2007, the Intergovernmental Panel on Climate Change (IPCC) estimated that by 2100 the sea level would rise by 0.18–0.59 metres. However, since then several researchers have suggested a rise of 1-1.5 metres would be more likely. Read the rest of this entry »

Could we cool the planet by copying volcanoes?

Mount Pinatubo erupts in 1991

Mount Pinatubo erupts in 1991

In 1991, Mount Pinatubo in the Philippines erupted violently, causing what so many scientists and politicians are trying to achieve these days: a reduction in global temperatures. The second largest volcanic eruption of the 20th century, Pinatubo threw approximately 20 billion tonnes of sulphur dioxide (SO2) into the air. Afterwards, the SO2 caused a proportion of the sun’s energy falling on the planet to be reflected back out into space. 1992 and 1993 were the two coolest years of the 1990s.

So, perhaps man could create a similar effect that would balance out any dangerous temperature rises. Or so suggests Stewart Brand, a biologist by training, and fountain of ideas, who I saw talk on Monday to promote his new book “Whole Earth Discipline”. Much of what Brand said addressed how to solve the problems that global warming will cause.

Brand would rather governments not step in and try to take charge of the response to global warming. However, he highlights the burning of coal for electricity as a big contributor to the greenhouse effect, and admits that governments will probably have to step in to cut back on this.

Likewise his other solutions – including increased uptake of nuclear power, wider acceptance of genetically-modified foods – need to be achieved on city-, country- or planet-wide scales. This is some way from what Simple Climate hopes to address – what any single individual can do. So, when this was the subject of the very last question of the evening even Brand, with his expertise, struggled.

Brand's new book, "Whole Earth Discipline".

Brand's new book

What he eventually advised was that each of us try and join in the “conversation”, about the issue. Whether we’re among those that he suggests take an almost religious, unshakeable, stand on the matter, either the believers, or the “denialists”. Or whether we’re among the group he calls “warmers”, people close to the scientific data that are convinced that man-made climate change is happening, which includes the vast majority of climatologists. And even the sceptics, those who question whether the climatologists have it right on scientific grounds and who Brand expects would continue to do so, even if the climatologist changed their minds. If everyone makes their voices heard, the right ideas and actions will emerge.

And on the matter of cooling the planet by copying volcanoes? Well, after seeing Brand I looked at a review paper from the prestigious science journal Nature in 1995 examining the effects of Pinatubo. It points out that as well as cooling the planet, the increase in atmospheric SO2 attacked atmospheric ozone. With the world having just about successfully dealt with this one environmental threat – the hole in the ozone layer – do we want to literally open it up all over again? As Brand himself said on the matter: “More science needed”.


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