Archive for 23 settembre 2010

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Environment – Climate Change
Climate ChangeClimate change is already happening and represents one of the greatest environmental, social and economic threats facing the planet. The European Union is working actively for a global agreement to control climate change and is taking domestic action to achieve substantial reductions in its own contribution. It is also developing a European strategy for adapting to climate change. The Fourth Assessment Report (AR4) of the Intergovernmental Panel on Climate Change (IPCC) shows that the Earth’s average surface temperature has risen by 0.76° C since 1850. Most of the warming over the past 50 years is very likely to have been caused by emissions of carbon dioxide (CO2) and other ‘greenhouse gases’ from human activities. Without action to reduce these emissions, the global average temperature is likely to rise by a further 1.8-4.0°C this century, and by up to 6.4°C in the worst case scenario, the IPCC projects. Even the lower end of this range would take the temperature increase since pre-industrial times above 2°C – the threshold beyond which many scientists believe irreversible and possibly catastrophic changes would become more likely.

The European Union has long been at the forefront of international efforts to combat climate change and was instrumental in the development of the two United Nations climate treaties, the 1992 UN Framework Convention on Climate Change (UNFCCC) and the Kyoto Protocol, agreed in 1997.The EU has also been taking steps to limit its greenhouse gas emissions since the early 1990s.

In 2000 the European Commission launched the European Climate Change Programme (ECCP) which has led to the adoption of a wide range of new policies and measures, including the pioneering EU Emissions Trading System.

The Kyoto Protocol requires the 15 countries that were EU members at the time (‘EU-15’) to reduce  their collective emissions in the 2008-2012 period to 8% below 1990 levels. Emissions monitoring and projections show that the EU-15 is well on track to meet this target.

In 2007 EU leaders endorsed an integrated approach to climate and energy policy and committed to transforming Europe into a highly energy-efficient, low carbon economy. They made a unilateral commitment that Europe would cut its emissions by at least 20% of 1990 levels by 2020. This commitment is being implemented through a package of binding legislation.

The EU has also offered to increase its emissions reduction to 30% by 2020, on condition that other major emitting countries in the developed and developing worlds commit to do their fair share under a future global climate agreement. This agreement should take effect at the start of 2013 when the Kyoto Protocol’s first commitment period will have expired.

The Copenhagen Accord reached in December 2009 represents a step towards such an agreement. The EU is pressing for a global deal that is ambitious, comprehensive and legally binding.

New Map Offers a Global View of Health-Sapping Air Pollution

In many developing countries, the absence of surface-based air pollution sensors makes it difficult, and in some cases impossible, to get even a rough estimate of the abundance of a subcategory of airborne particles that epidemiologists suspect contributes to millions of premature deaths each year. The problematic particles, called fine particulate matter (PM2.5), are 2.5 micrometers or less in diameter, about a tenth the fraction of human hair. These small particles can get past the body’s normal defenses and penetrate deep into the lungs.

To fill in these gaps in surface-based PM2.5 measurements, experts look toward satellites to provide a global perspective. Yet, satellite instruments have generally struggled to achieve accurate measurements of the particles in near-surface air. The problem: Most satellite instruments can’t distinguish particles close to the ground from those high in the atmosphere. In addition, clouds tend to obscure the view. And bright land surfaces, such as snow, desert sand, and those found in certain urban areas can mar measurements.

However, the view got a bit clearer this summer with the publication of the first long-term global map of PM2.5 in a recent issue of Environmental Health Perspectives. Canadian researchers Aaron van Donkelaar and Randall Martin at Dalhousie University, Halifax, Nova Scotia, Canada, created the map by blending total-column aerosol amount measurements from two NASA satellite instruments with information about the vertical distribution of aerosols from a computer model.

Global satellite-derived map of PM2.5 averaged over 2001-2006.  <b>Credit:</b> Dalhousie University, Aaron van Donkelaar

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Global satellite-derived map of PM2.5 averaged over 2001-2006. Credit: Dalhousie University, Aaron van Donkelaar

Their map, which shows the average PM2.5 results between 2001 and 2006, offers the most comprehensive view of the health-sapping particles to date. Though the new blending technique has not necessarily produced more accurate pollution measurements over developed regions that have well-established surface-based monitoring networks, it has provided the first PM2.5 satellite estimates in a number of developing countries that have had no estimates of air pollution levels until now.

The map shows very high levels of PM2.5 in a broad swath stretching from the Saharan Desert in Northern Africa to Eastern Asia. When compared with maps of population density, it suggests more than 80 percent of the world’s population breathe polluted air that exceeds the World Health Organization’s recommended level of 10 micrograms per cubic meter. Levels of PM2.5 are comparatively low in the United States, though noticeable pockets are clearly visible over urban areas in the Midwest and East.

“We still have plenty of work to do to refine this map, but it’s a real step forward,” said Martin, one of the atmospheric scientists who created the map.”We hope this data will be useful in areas that don’t have access to robust ground-based measurements.”


NASA – New Map Offers a Global View of Health-Sapping Air Pollution