We Speak For Earth
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perscientiamlibertas A Matter of the Most Pleasant Fraternal Confidence
Recent Global Warming Slowed by Volcanoes
Global average temperatures have been rising in recent years, but not as much as they might have, thanks to a series of small-to-moderate-sized volcanic eruptions that have spewed sunlight-blocking particles high into the atmosphere. That’s the conclusion of a new study, which also finds that microscopic particles derived from industrial smokestacks have done little to cool the globe.
Between 2000 and 2010, the average atmospheric concentration of carbon dioxide — a planet-warming greenhouse gas — rose more than 5%, from about 370 parts per million to nearly 390 parts per million. If that uptick were the only factor driving climate change during the period, global average temperature would have risen about 0.2°C, says Ryan Neely III, an atmospheric scientist at the University of Colorado, Boulder. But a surge in the concentration of light-scattering particles in the stratosphere countered as much as 25% of that potential temperature increase, he notes.
According to satellite data, a measure of the light-scattering ability of the stratospheric particles, called aerosols, rose on average between 4% and 7% each year between 2000 and 2010. (The more incoming sunlight is scattered back into space, the stronger the cooling effect.) But researchers have strongly debated the source of those aerosols, Neely says. While many teams have suggested that the aerosols came from small-to-mid-sized volcanic eruptions, a few others have proposed that they originated in Asian smokestacks. Their rationale: Emissions of sulfur dioxide in India and China grew about 60% during the decade, and atmospheric convection associated with the region’s summer monsoon provides a way for watery droplets containing that gas to reach the stratosphere then diffuse around the world.
The commitment to reduce greenhouse gas emissions should be allocated based on countries’ historic responsibility for the emissions. This logic was recognized early on in climate negotiations. But the countries are still disputing how it should be interpreted and applied.
When the United Nations Framework Convention on Climate Change was adopted in 1992, “historic responsibility” was established – that is, the countries that release the most greenhouse gases also have a greater responsibility to reduce emissions. To some extent this is also reflected in the convention, where the industrialised countries (OECD) have made a greater commitment than the developing countries.
But despite twenty years of negotiations, there is still no prevailing consensus on how the historic responsibility should be interpreted in detail. Rather, the conflict has become sharper. So argues Mathias Friman, who recently defended his doctoral thesis at Water and Environmental Studies (WES) at Linköping University in Sweden. In his study, he brings out two different interpretations of the historic responsibility, which have come out in climate negotiations.
“On one hand there is proportional responsibility, namely responsibility in proportion to impact on the climate. This gives the industrialised countries the greatest responsibility, and has given rise to a number of different models; there are thousands of ways to calculate this.”
“Another interpretation is moral responsibility, where the countries contribute to reductions based on their capacity. This also gives the industrialised countries greater responsibility, but opens up a way for the new developing countries to make a greater commitment.”
While the developing countries argued for proportional responsibility, in accordance with the principle “the polluter pays”, it was countered by the rich countries with two main arguments: One is that it is far too difficult to calculate exactly what proportional responsibility means in the commitment. The other is that we cannot hold previous generations responsible for something they didn’t know was harmful.
The rich countries prefer to talk about moral responsibility, more based on capacity. This way, rapidly developing countries like Brazil, China, Mexico, South Africa, and India could also have greater commitments imposed as their capacity increases. China, for its part, has argued for historic responsibility calculated on a per capita basis.
Up until 2007 it historic responsibility was fairly silent in the negotiations, Friman states. The concept had been accepted, but the issue had been referred to an advisory body where various calculation models were worked out. Now, there are a range of such models and it is more difficult to blame it on “it can’t be calculated,” he says. The issue of historic responsibility has returned to the negotiations, and the conflict has become sharper.
“It is understandable that the conflict will heat up considerably now that historic responsibility will actually be translated into a range of commitments,” Friman says, citing the United States as an example:
The US says it wants to take the lead in climate work through committing to decreasing its emissions by 3% up through 2020, as compared with 1990. On the other hand, if the responsibility would be calculated proportionately, the US would end up with a reduction requirement closer to 50-60%.
Right now it’s difficult to see a solution, Friman states, who in his thesis also reviewed the rules for dialogues within the climate convention. Rules for decision-making are absent, and the mechanisms for conflict resolution other than through negotiation are very weak. Among other things, this means that all decisions must be taken in consensus and that agreements must be accepted or rejected in their entirety – something that paves the way for sharp contradictions and intense conflicts, he states.
Further reading:
Reducing carbon dioxide emissions may not be enough to curb global warming, say Stanford University scientists. The solution could require carbon-negative technologies that actually remove large amounts of CO2 from the atmosphere.
Decaying plants contribute to global warming by releasing carbon dioxide into the air. Now researchers are converting plant wastes into biochar - a charcoal-like substance that can be used as fertilizer to permanently lock the carbon underground. These lettuce plots in Minnesota were amended with 20,000 pounds of macadamia-nutshell biochar per acre to evaluate the effect on crop yield, soil fertility and greenhouse gas production from the field. Image: Amanda Bidwell, USDA/Agricultural Research Service.
In his Feb. 12 State of the Union address, President Obama singled out climate change as a top priority for his second administration. “We can choose to believe that Superstorm Sandy, and the most severe drought in decades, and the worst wildfires some states have ever seen were all just a freak coincidence,” he said. “Or we can choose to believe in the overwhelming judgment of science – and act before it’s too late.”
Four years ago, the president addressed rising global temperatures by pledging a 17 percent cut in carbon dioxide (CO2) and other greenhouse gas emissions in the United States by 2020, and an 80 percent cut by 2050. The administration has taken a number of steps to meet those goals, such as investing billions of dollars in wind, solar and other carbon-neutral energy technologies.
But reducing CO2 emissions may not be enough to curb global warming, according to Stanford scientists. The solution, they say, could also require developing carbon-negative technologies that remove large amounts of CO2 from the atmosphere. Their findings are summarized in a report by Stanford’s Global Climate and Energy Project (GCEP).
“To achieve the targeted cuts, we would need a scenario where, by the middle of the century, the global economy is transitioning from net positive to net negative CO2 emissions,” said report co-author Chris Field, a professor of biology and of environmental Earth system science at Stanford. “We need to start thinking about how to implement a negative-emissions energy strategy on a global scale.”
In the GCEP report, Field and lead author Jennifer Milne describe a suite of emerging carbon-negative solutions to global warming – from bioenergy technologies to ocean sequestration. Many of the examples cited were initially presented at a negative carbon emissions workshop hosted by GCEP in 2012.
Former University of Michigan graduate student Katy Keller with a hand on eroded and melting permafrost near Toolik Lake, Alaska. The gully erosion seen here is a type of thermokarst failure, formed when ice-rich, permanently frozen soils are warmed and thawed. Image: George Kling
Ancient carbon trapped in Arctic permafrost is extremely sensitive to sunlight and, if exposed to the surface when long-frozen soils melt and collapse, can release climate-warming carbon dioxide gas into the atmosphere much faster than previously thought.
University of Michigan ecologist and aquatic biogeochemist George Kling and his colleagues studied places in Arctic Alaska where permafrost is melting and is causing the overlying land surface to collapse, forming erosional holes and landslides and exposing long-buried soils to sunlight.
They found that sunlight increases bacterial conversion of exposed soil carbon into carbon dioxide gas by at least 40 percent compared to carbon that remains in the dark. The team, led by Rose Cory of the University of North Carolina, reported its findings in an article to be published online Feb. 11 in the Proceedings of the National Academy of Sciences.
“Until now, we didn’t really know how reactive this ancient permafrost carbon would be — whether it would be converted into heat-trapping gases quickly or not,” said Kling, a professor in the U-M Department of Ecology and Evolutionary Biology. EEB graduate student Jason Dobkowski is a co-author of the paper.
“What we can say now is that regardless of how fast the thawing of the Arctic permafrost occurs, the conversion of this soil carbon to carbon dioxide and its release into the atmosphere will be faster than we previously thought,” Kling said. “That means permafrost carbon is potentially a huge factor that will help determine how fast the Earth warms.”
Tremendous stores of organic carbon have been frozen in Arctic permafrost soils for thousands of years. If thawed and released as carbon dioxide gas, this vast carbon repository has the potential to double the amount of the heat-trapping greenhouse gas in the atmosphere on a timescale similar to humanity’s inputs of carbon dioxide due to the burning of fossil fuels.
That creates the potential for a positive feedback: As the Earth warms due to the human-caused release of heat-trapping gases into the atmosphere, frozen Arctic soils also warm, thaw and release more carbon dioxide. The added carbon dioxide accelerates Earth’s warming, which further accelerates the thawing of Arctic soils and the release of even more carbon dioxide.
Recent climate change has increased soil temperatures in the Arctic and has thawed large areas of permafrost. Just how much permafrost will thaw in the future and how fast the carbon dioxide will be released is a topic of heated debate among climate scientists.
Emissions from coal power stations could be drastically reduced by a new, energy-efficient material that adsorbs large amounts of carbon dioxide, then releases it when exposed to sunlight.
In a study published today in Angewandte Chemie, Monash University and CSIRO scientists for the first time discovered a photosensitive metal organic framework (MOF) – a class of materials known for their exceptional capacity to store gases. This has created a powerful and cost-effective new tool to capture and store, or potentially recycle, carbon dioxide.
By utilising sunlight to release the stored carbon, the new material overcomes the problems of expense and inefficiency associated with current, energy-intensive methods of carbon capture. Current technologies use liquid capture materials that are then heated in a prolonged process to release the carbon dioxide for storage.
Associate Professor Bradley Ladewig of the Monash Department of Chemical Engineering said the MOF was an exciting development in emissions reduction technology.
Image: Chang’r/Flickr
Toronto – and other cities around the world – can significantly reduce greenhouse gas emissions by implementing aggressive but practical policy changes, says a new study by Professor Chris Kennedy and World Bank climate change specialist Lorraine Sugar .
Professor Kennedy and Sugar make the claim in ‘A low carbon infrastructure plan for Toronto, Canada,’ published in the latest issue of The Canadian Journal of Civil Engineering. The paper aims to show how cities can make a positive difference using realistic, achievable steps. Their research shows that it is technically possible for cities, even in Canada, to reduce their greenhouse gas emissions by 70 per cent or more in the long-term.
“This is the sort of reduction the international community is calling for, so we can avoid the potentially serious consequences of climate change,” said Professor Kennedy.
Professor Kennedy and Sugar note that more than half of the world’s population lives in urban areas and over 70 per cent of global greenhouse gas emissions can be attributed to cities.
“Cities are where people live, where economic activity flourishes,” said Sugar. “Cities are where local actions can have global impact.”
The study focuses on buildings, energy supply and transportation. Best practices as well as options and opportunities are detailed.
“It is possible for a Canadian city, in this case Toronto, to reduce its GHG emissions by the sort of magnitudes that the international scientific community have indicated are necessary globally to keep global temperature rise below 2 C,” Professor Kennedy and Sugar write.
“With current policies, especially cleaning of the electricity grid, Toronto’s per-capita GHG emissions could be reduced by 30 per cent over the next 20 years. To go further, however, reducing emissions in the order of 70 per cent, would require significant retrofitting of the building stock, utilization of renewable heating and cooling systems, and the complete proliferation of electric, or other low carbon, automobiles.”
The biggest obstacle is the city’s building stock, according to Professor Kennedy. Buildings have a lifespan measured in decades, so it takes time to replace older buildings with more energy-efficient ones.
The study arose out of a handbook Professor Kennedy and his students produced for the Toronto and Region Conservation Authority in 2010, Getting to Carbon Neutral: A Guide for Canadian Municipalities. In the current paper, he and Sugar wanted to demonstrate how cities could achieve measurable results by adopting the policies outlined in the guide.
Professor Kennedy, author of The Evolution of Great World Cities: Urban Wealth and Economic Growth (2011), teaches a course on the design of infrastructure for sustainable cities. He has consulted for the World Bank, the United Nations and the OECD on urban environment issues.
Further Reading:
In lakes and streams, fish and insects can help protect aquatic plants that gobble up greenhouse gas
Climate scientists note that Earth will suffer excessive warming if levels of carbon dioxide and other greenhouse gases in the atmosphere get much higher. That’s why scientists have been looking for ways to encourage living organisms to act like a sponge, mopping up and storing much of that carbon dioxide. These carbon-storing species include trees, grasses and algae.
The Microbial Communities of the Future
The world, it turns out, is getting warmer. The extent and precise contours of climate change may never be forecastable, but many scientists are working to test the repercussions of a warmer atmosphere, in order to both inform policy discussions and instigate difficult discussions about adaptation strategies.
Nicholas Bouskill, an ecologist at the University of California at Berkeley, is one such scientist. Through a carefully designed study of jungle floor patches in Puerto Rico, Bouskill and his team are hoping to determine how the microbial make-up of soil changes in response to repeated periods of dryness. “These locations are likely to experience changes in the magnitude of rainfall, with increased drought and longer dry periods,” he writes in a recent edition of the ISME Journal.
It wasn’t necessarily clear how a drier environment would impact the microbial community since soil moisture is a double edged sword: Too much of it, and the diffusion of important gases in and out of the soil is limited; too little, and nutrients might not reach the microbes in sufficient quantities. So how, and how quickly, might soil-based microbial communities change in response to less water? Bouskill sought answers by tracking diversity shifts in plots of soil cut off from rain throughfall for the first time and those experiencing a second artificial drought.
A University of British Columbia study of American attitudes toward climate change finds that local weather – temperature, in particular – is a major influence on public and media opinions on the reality of global warming.
The study, published today by the journal Climatic Change, finds a strong connection between U.S. weather trends and public and media attitudes towards climate science over the past 20 years – with skepticism about global warming increasing during cold snaps and concern about climate change growing during hot spells.
“Our findings help to explain some of the significant fluctuations and inconsistencies in U.S. public opinion on climate change,” says UBC Geography Prof. Simon Donner who conducted the study with former student Jeremy McDaniels (now at Oxford University).
The researchers used 1990-2010 data from U.S. public opinion polls and media coverage by major U.S. newspapers, including The New York Times, Washington Post, The Wall Street Journal and USA Today. They evaluated the relationship between average national temperatures and opinion polls on climate change, along with the quantity and nature of media editorials and opinion pieces related to climate change.
While many factors affect climate change attitudes – political views, media coverage, personal experience and values – the researchers suggest that headline-making weather can strongly influence climate beliefs, especially for individuals without strong convictions for or against climate change.
“Our study demonstrates just how much local weather can influence people’s opinions on global warming,” says Donner. “We find that, unfortunately, a cold winter is enough to make some people, including many newspaper editors and opinion leaders, doubt the overwhelming scientific consensus on the issue.”
Increasingly hot summer weather could cause a fall in crop yields over the next two decades unless farming techniques are improved more quickly, scientists at the University have found.
High temperatures are having an increasingly damaging effect on maize (sweetcorn) in France – the largest supplier of the crop to the UK – which may explain a recent slowdown in the trend towards higher yields, according to researchers at the Universities of Leeds, Reading and Exeter.
Improvements in agricultural technology, such as fertilisers and new crop varieties, will need to increase yields by up to 12% by the 2020s to be confident about offsetting future decreases in yield from heat stress.
However, the current rate of improvement, driven by technological innovation, is not quick enough to meet such a high target, says research published today in the journal Global Change Biology.
Professor Andrew Challinor, from the University of Leeds’ School of Eearth & Environment, said: “Feeding a growing population as climate changes is a major challenge, especially since the land available for agricultural expansion is limited. Supplies of the major food crops could be at risk unless we plan for future climates.”
Dr Ed Hawkins, from the National Centre for Atmospheric Science (NCAS) at the University of Reading, said:
“Our research rings alarm bells for future food security. Over the last 50 years, developments in agriculture, such as fertilisers and irrigation, have increased yields of the world’s staple foods, but we’re starting to see a slowdown in yield increases. Our research into maize suggests the increasing frequency of hot days across the world might explain some of this slowdown.
“We expect hot days to become more frequent still, and our work on maize suggests that current advances in agriculture are too slow to offset the expected damage to crops from heat stress in the future.”
