Ancient civilizations emitted greenhouse gasses, too; the red and orange dots above
mark indirect measures of methane in the atmosphere over the past two millennia.
Scientists have thought that humans only started emitting significant quantities of greenhouse gasses in the 19th century, after the Industrial Revolution—and the fossil fuels that powered it—took hold. But a study in Nature today suggests that our history as heavy emitters stretches back much farther, to the charcoal fires of the Roman Empire and the intensive agriculture of Han China.
To examine carbon emissions past, the research team analyzed more than 50 ice cores from Greenland, gauging levels of the greenhouse gas methane in Earth’s atmosphere going back to 100 B.C. They looked at specific carbon signatures in the methane to determine whether it came from burning coal and other materials—meaning humans might have been involved—or a natural biological process, then used mathematical models to further narrow down manmade emissions from naturally occurring ones. Human emissions, they found, were noticeable, though minuscule compared to post-industrial levels; only perhaps 10% human methane emissions over the past 2,000 years were produced before 1800. For a time when there were far fewer people around, however, that’s still a lot of methane to be sending off into the atmosphere.
Cap-and-trade is coming to California. The market-based system intended to cut greenhouse gas emissions is the key part of the Golden State’s effort, set into law four years ago, to cut its emissions to 1990 levels by 2020. Yesterday the California Air Resources Board finally approved the complex set of rules, which will go into effect in 2012.
Power plants, refineries and other industrial facilities that emit carbon dioxide and can’t cut their emissions by the required amount will be able to obtain pollution allowances from the state or buy them from other emitters with excess allowances. [Wall Street Journal]
Cap-and-trade is widespread in Europe, but California‘s plan would be the first large-scale, legally mandated version of this idea to get going in the United States.
“We’re inventing this,” said Mary Nichols, chairwoman of the state’s air quality board. “There is still going to be quite a bit of action needed before it becomes operational.” She said California is trying to “fill the vacuum created by the failure of Congress to pass any kind of climate or energy legislation for many years now.” [USA Today]
Polar bears, the poster-species for climate change, have been the subject of reports about new or growing threats in 2010: One story noted that the warming Arctic is pushing grizzlies north into polar bear territory, while another questioned whether polar bears can change their diet as their icy habitat melts. But the journal Nature this week brought an antidote to all that doom and gloom. A study modeling the Arctic climate suggests that it’s still not too late to protect the polar bear habitat, and therefore save the polar bear. The world just needs to reduce its greenhouse gas emissions.
The question is one of tipping points: Is the total demise of the Arctic summer sea ice already inevitable, or could a slowing of emissions also slow down the ice loss?
The dramatic retreat of Arctic sea ice in the summer of 2007 prompted some researchers to warn that the system may have reached a tipping point that would lead to the disappearance of summer sea ice within the next several decades, regardless of actions humans took to reduce greenhouse-gas emissions. That concern, in turn, helped elevate the polar bear to climate-icon status and reportedly fed into then-President George W. Bush’s decision in 2008 to list the bear as “threatened” under the Endangered Species Act. The new study, however, finds no “tipping point” now or in this century in Arctic sea-ice decline, but rather a relatively steady fall-off in ice extent as average temperatures increase. [Christian Science Monitor]
Study author Steven Amstrup, formerly of the U.S. Geological Survey and now at Polar Bears International, modeled five different scenarios for greenhouse emissions in the future. He saw a linear relationship between rising temperatures brought on by those emissions and the retreat of Arctic ice. What he didn’t see was a sharp sudden drop, a point at which crossing some temperature boundary led to an irrevocable disappearance of the ice that would doom the bears.
When the Cancun Climate Summit began, we mentioned the modest goals most nations set going in (especially in the wake of 2009′s messy Copenhagen meeting). Indeed, the United Nations climate meeting in Mexico didn’t shoot for the stars in terms of emissions reductions, but the nations assembled at least agreed to a few limited proposals and set the stage for next year.
The agreement is not a legally binding one, but it includes:
1. The package known as the Cancún Agreements gives the more than 190 countries participating in the conference another year to decide whether to extend the frayed Kyoto Protocol, the 1997 agreement that requires most wealthy nations to trim their emissions while providing assistance to developing countries to pursue a cleaner energy future. [The New York Times]
Kyoto’s targets were for the year 2012. The question for the 2011 meeting in South Africa, then, will be whether it’s possible to get everyone on board with a Kyoto extension or some other emissions reduction agreement. (Cancun did bring one promising sign, as the nations agreed in principle to allow outside inspection to check the validity of their emissions cuts.)
2. It includes a scheme to provide financial support for countries to preserve their forests, in a bid to combat deforestation which accounts for almost a fifth of global annual emissions, and makes progress on how countries’ actions are going to be monitored and verified. [The Independent]
Twenty miles outside of Abu Dhabi, in the scorching desert of the United Arab Emirates, the new planned city of Masdar is nearly ready for its close-up. This weekend The New York Times reported from the experimental zero-carbon closed community, funded by stacks of oil money, which is now prepared to take on its first inhabitants. The urban design is simultaneously sleek and unsettling, raising the questions: Is this what the city of the future will look like, and would that be a good thing?
Masdar’s main designer, Norman Foster, hits all the notes that make green ears perk up: excluding any carbon-based energy sources, using simplified “sustainable” architecture, and learning from the lessons of the past, even going back as far as centuries-old desert settlements.
Cooking all your meals on an old-fashioned stove indoors is bad for you and bad for the Earth: The smoke from those fires causes heart and lung problems for millions of people, the soot contributes to global warming and glacier melt, and the need for so much wood drives deforestation. Yet, out of necessity, nearly half the people in the world cook this way.
This week, a United States and United Nations-backed effort took the first tiny steps to try to turn that around. Secretary of State Hillary Clinton says that the U.S. will give $50 million in seed money to the new Global Alliance for Clean Cookstoves, an organization with the intention of providing cleaning-burning cooking stoves to families around the world. Other partners will each provide $10 million.
Yesterday Senators John Kerry and Joe Lieberman rolled out their new climate bill, the American Power Act. The 987-page piece of text was driven by what we’ve come to expect in climate legislation: Concrete targets for reducing carbon dioxide emissions a certain percentage by a certain year. But, an international group of economists and environmental scientists are saying, that approach is doomed to failure, and this is the time to change.
The Hartwell Paper, a product of 14 different authors working since February, came out this week to coincide with the release of the climate bill. The assessment is blunt: Reaching agreements like the Kyoto Protocols to reduce carbon emissions has been the primary means of addressing climate change since the mid-1980s, and it hasn’t worked. With the high-profile flop that was the 2009 climate summit in Copenhagen, the authors argue this is the chance to drive a new course on climate policy, one not singularly focused on CO2.
The Hartwell authors don’t downplay the importance of CO2 as a greenhouse gas; rather, they point to the silliness of being so fixated on that one compound; the Earth’s climate, after all, is a terribly complex system:
That is frustrating for politicians. So policy makers frequently respond to wicked problems by declaring ‘war’ on them, to beat them into submission and then move on. Indeed, almost any ‘declaration of war’ that is metaphorical rather than literal is a reliable sign that the subject in question is ‘wicked’. So, we have the war on cancer, the war on poverty, the war on drugs, the war on terror and now the war on climate change.
When researchers rack up the carbon emitted across the world, the standard trends emerge: Europeans put less CO2 into the atmosphere than Americans, but China’s rapid ascent is sending its emissions shooting past those of the United States. However, this week in the Proceedings of the National Academy of Sciences, Stanford University researchers attempt to rejigger the numbers to reflect not just where the emissions are produced, but who is responsible for them—who’s buying and consuming the products that cause those emissions.
After study global trade databases, Steven Davis and Ken Caldiera say that in 2004, 23 per cent of global CO2 emissions – some 6.2 gigatonnes – went in making products that were traded internationally. Most of these products were exported from China and other relatively poor countries to consumers in richer countries [New Scientist]. The researchers say that developed countries outsource about a third of the carbon dioxide emissions connected to their consumption.
This week in Nature Geoscience, a cadre of scientists going by the name Global Carbon Project will publish a meta-analysis of global carbon emissions. The study led to headlines like, “Global CO2 emissions to drop 2.8 pct in ’09: report,” and many others more in the ominous vein of “Earth ‘heading for 6C (6 degrees Celsius)’ of warming.” So how did both headlines come from the same study?
This year’s dip is correct: “In 2009, it is likely that the global financial crisis will cause global emissions to actually fall by a couple of percent,” said Michael Raupach, co-author of the report and co-chair of the Global Carbon Project [Reuters]. But, he says, the carbon cut will be short-lived if the recession ends.
In that case, the researchers say, the world will return to its normal trend. Since 2000 emissions have been rising by an average 3.4 per cent every year, compared to one per cent in the 1990s [The Telegraph]. Overall, worldwide emissions rose by 29 percent from 2000 to 2008, and the scientists put forward that 6 degrees Celsius global warming figure as a worst-case scenario—what could happen if the overall rising trend continued unabated.