Dump fossil fuels for the health of our hearts

Air quality in London on April 3, 2014 fell to a level where it became hard to see normally-visible skyscrapers. Conditions hit a 9/10 risk ranking  thanks to a combination of pollution and dust blown in from the Sahara desert. Tackling such pollution could immediately improve people's health, stresses New York University's George Thurston. Image copyright David Holt, used via Flickr Creative Commons license.

Air quality in London on April 3, 2014 fell to a level where it became hard to see normally-visible skyscrapers. Conditions hit a 9/10 risk ranking thanks to a combination of pollution and dust blown in from the Sahara desert. Tackling such pollution could immediately improve people’s health, stresses New York University’s George Thurston. Image copyright David Holt, used via Flickr Creative Commons license.

Sometimes when I blow my nose and – inevitably – look into my handkerchief, I see that my snot is black. It doesn’t happen when I’m at home, in the small English city of Exeter, only when I’m in London. It’s a clear sign of the extra pollution I’m inhaling when I’m in the capital – one backed up by data published last week by Public Health England. Its striking report says that in 2010 73 deaths per thousand in the London borough of Waltham Forest, where my girlfriend’s sister lives, could be put down to grimy air. For Exeter, the figure was just 42 per 1000. Across the whole of England, pollution killed 25,002 people in 2010, or 56 of every 1000 deaths nationwide.

But wherever you live, air pollution will become even more important as the climate changes, while fighting this scourge could also help the world bring global warming under control. “There’s more than enough rationale for controlling emissions based on the health effects and the benefits that we get as a society from getting off of fossil fuels,” New York University’s George Thurston told me. “Those are the benefits that are going to accrue to the people who do the clean-up – locally and immediately, not fifty years from now.”

Public Health England is trying to draw attention to ‘particulate matter’, or dust, less than 2.5 micrometres in diameter, too small to see with our naked eye. You won’t find this ‘PM2.5’ pollution listed as people’s cause of death – it’s likely to be down as a heart attack or lung cancer. George has run huge studies in the US to help work out exactly how much such dust worsens people’s health. One study for the American Cancer Society followed 1.2 million men and women originally enrolled in 1982. Another, started in 1995, tracked over 500,000 US retirees over the following decade. And he was also a part of a worldwide project that last year showed ‘global particulate matter pollution is a major avoidable risk to the health of humankind’. Read the rest of this entry »

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Could pollution be stopping warming’s impact on rain?

A brown cloud of pollution over Phoenix, Arizona. Brown clouds of aerosol pollutant particles could be overwhelming the expected changes in rainfall arising from increasing greenhouse gas levels in the air. Credit: Flick/Flickr

A brown cloud of pollution over Phoenix, Arizona. Brown clouds of aerosol pollutant particles could be overwhelming the expected changes in rainfall arising from increasing greenhouse gas levels in the air. Credit: Flick/Flickr

Contrary to previous predictions and measurements, rain patterns have got more uniform as the world has warmed over the past 70 years. So say Michael Roderick and his teammates from Australian National University, Canberra, who’ve developed an ‘accounting system’ that looks closely at where and when rain fell. And the reason could be aerosols – clouds of pollutant particles – produced by humans. “The existing dogma is that increasing greenhouse gas concentrations in the atmosphere have raised rainfall variability,” Michael told me. “In that context, our results emphasise the importance of taking a whole system approach in trying to understand how something complex, like rainfall, is changing in different places.”

When scientists want to understand how climate has been changing over large areas, they usually look at maps of long-term average data that ignore patterns of change in time, Michael explained. When they want to look at how it’s changed over time, they usually either look at a single place or a worldwide average, which ignores patterns in where the changes are. But Michael, along with fellow scientists Fubao Sun and Graham Farquhar, wanted to find a way to link place and time.

To do this Fubao started from a common statistical test called Analysis of Variance or ANOVA. Normally it’s used to compare the effect of different “treatments” – such as a variety of temperatures – on the yield of a crop, for example. In such cases each treatment must be repeated more than once, giving different “replicates”, for the test to be valid. ANOVA can be used to give a value for variance – a measure that shows how spread out an experiment’s measurements are. Read the rest of this entry »

Developed countries duck warming responsibility

Beijing Normal University's John Moore, Xuefeng Cui and their collegues assessed the relative impact on future warming if developed and developing countries follow the pledges to cut CO2 emissions they made at the UN climate change conference in Cancún, Mexico, in November 2010, shown here. Credit: UNclimatechange/Flickr

Beijing Normal University’s John Moore, Xuefeng Cui and their collegues assessed the relative impact on future warming if developed and developing countries follow the pledges to cut CO2 emissions they made at the UN climate change conference in Cancún, Mexico, in November 2010, shown here. Credit: UNclimatechange/Flickr

Disputes between leaders of rich and poor countries currently mean little comes from meetings where they’re meant to draw up plans to slow and stop climate change. But developed countries’ existing promises would achieve just 1/3 of any warming slowdown, even though we’re responsible for more than 2/3 of CO2 emissions before 2005. That’s according to a team of mainly Chinese researchers who have tried to settle these fights using “earth system” models, considering both natural and human factors. “Developed countries need to take more responsibility in climate mitigation by cutting more carbon emissions and helping developing countries to control carbon emission while maintaining economic development,” said Xuefeng Cui from Beijing Normal University (BNU).

At the United Nations’ Climate Change Conference in Cancún, Mexico, in November 2010, leaders agreed to try and limit the global temperature rise to 2°C higher than pre-industrial levels. They also agreed that doing this needs deep, but fair, cuts in the amount of warming-causing greenhouse gases humans emit. But they still argue about how to share those cuts. That prompted Cui and his team to make an unusual effort to use science to show what is fair.  “The arguments in the IPCC process demand some fact-based reasoning rather than just the ‘blame game’,” team member John Moore told Simple Climate. “Our study is the first interdisciplinary study by climate, social, economic, and ecological scientists and policy makers to look at the historical responsibilities and effect of future mitigation by applying state-of-art earth system models,” Xuefeng added.

Getting such a broad view meant that the team had to develop entirely new methods for their research, published online in the scientific journal Proceedings of the National Academy of Sciences of the USA on Monday. “Most scientists are interested in the real impacts rather than assigning responsibilities,” Moore said. “These are more abstract philosophical and moral points than they tend to consider.” It took a 37-strong team of scientists to develop the approach, and one of the two earth systems models, they used. Whole earth system models are needed to understand the effects plants, animals, land and oceans have on climate. Read the rest of this entry »

Soot and methane cuts promise threefold benefits

Vehicles are a significant source of black carbon and other pollutants in many countries. Credit: Caramel/flickr

Vehicles are a significant source of black carbon and other pollutants in many countries. Credit: Caramel/flickr

Limiting methane and soot emissions would save lives and keep farming output high, as well as playing an important role in fighting global warming. That’s according to some 70 scientists who have reviewed the available research on these substances for the United Nations Environment Partnership (UNEP). Such cuts were also surprisingly feasible, with just 16 ways of limiting emissions providing about 90 percent of the possible climate benefit from a list of 2000 control measures.

“We estimate that adoption of the 16 control measures we considered would save about 2 million lives a year and save 50 million tons of crops a year,” said NASA’s Drew Shindell, who led the project. “For climate, putting control measures in place could eliminate about half the warming we’ll otherwise face over the next 40 years.” Read the rest of this entry »

Atlantic cold tongue tells of humans’ climate impact

Wind waves depend on wind speed and have long been logged by ship crews. Ocean wind data corrected with wind-wave heights suggests a slow down of the southeast trade winds in the equatorial Atlantic. Credit: Image courtesy of Ship DAVID STARR JORDAN, NOAA Photo Library.

Wind waves depend on wind speed and have long been logged by ship crews. Ocean wind data corrected with wind-wave heights suggests a slow down of the southeast trade winds in the equatorial Atlantic. Credit: Image courtesy of Ship DAVID STARR JORDAN, NOAA Photo Library.

Humanity has significantly altered the climate in the tropical Atlantic between 1950 and 2009, gradually weakening the area’s trade winds, University of Hawaii at Manoa researchers say. That effect is caused by burning fossil fuels, Hiroki Tokinaga and Shang-Ping Xie explain. However, it is more directly driven by the aerosols of soot and sulfur-based particles this releases than global warming caused by the resulting CO2 greenhouse gas emissions.

Falls in aerosol emissions now look set to reverse this trend, Tokinaga notes, showing how government actions can influence the environment. “Human-produced aerosol emissions had continuously increased until the 1970s, but then they started to decrease because of legislation in North America and Europe,” he told Simple Climate. “Increased greenhouse gas forcing contributes to a broader warming of the tropical Atlantic. Another climate shift might happen when the increased greenhouse gas forcing gets stronger than the aerosol forcing in the next few decades.” Read the rest of this entry »

Arctic warming full ahead

It may be plunging towards the depths of its long, dark, cold, winter now, but 2010 has been another hot year for the Arctic. Air temperatures over Greenland reached the highest directly recorded levels, according to the 2010 Arctic Report Card. This meant that ice melted from the island’s huge inland sheet for 1 month longer than the average melt period over the past 30 years.

This summary, compiled by the US National Oceanic and Atmospheric Administration (NOAA), also documents an “exceptional” loss of glaciers around Greenland in 2010. 110 square miles of ice, four times the area of Manhattan Island, entered the ocean in the single largest glacier loss at Petermann glacier. “There is now no doubt that Greenland ice losses have accelerated,” the report underlines. “The implication is that sea level rise projections will again need to be revised upward.”

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When should we stop emitting?

Bob Kopp, AAAS science and technology policy fellow.

Bob Kopp, AAAS science and technology policy fellow.

Bob Kopp says that we have good records showing that the amount of CO2 in the atmosphere is currently the highest it’s been in 800,000 years. He should know, as he is a paleoclimatologist – a scientist who studies climate change through Earth’s history. Beyond these higher-quality records that are trapped deep in the ice at our poles, lower quality evidence suggests that CO2 levels may even be the highest for 3 million years. “If we keep doing what we’re doing, then by the end of the century CO2 levels will probably be about as high as they have been in about 40 million years,” Kopp said. “40 million years ago, temperatures were on the order of 5-10ºC warmer than today and there weren’t permanent ice sheets on the planet.”

CO2 in the atmosphere takes time to have an effect on the rest of the climate, Kopp points out, so if we continued to emit as we are and then stopped, the warming would carry on for many years. “If we don’t stabilize [greenhouse gas concentrations] until after the end of the century, then we’ll be on track over the course of centuries, maybe at most a few millennia, to end up with a world that looks more like the world did 40 million years ago than it has since the human civilisation has grown up and thrived,” he said. Read the rest of this entry »