A new study from NASA's Goddard Institute for Space Studies has identified on-road transportation as the most significant overall source contributing to global warming. Power generation, while having the greatest total impact, also includes a large number of compounds that increase cloud reflectivity and provide other effects to offset some of the warming they are responsible for.

In the study, rather than looking at specific chemicals and compounds, the range of airborne pollutants is broken down by economic sector. The study looks at the range of gases and aerosols that are released by each of 13 sectors of the economy, and finds that on-road transportation has the greatest overall effect on global warming.

"Cars, buses, and trucks release pollutants and greenhouse gases that promote warming, while emitting few aerosols that counteract it. The researchers found that the burning of household biofuels -- primarily wood and animal dung for home heating and cooking -- contribute the second most warming. And raising livestock, particularly methane-producing cattle, contribute the third most. On the other end of the spectrum, the industrial sector releases such a high proportion of sulfates and other cooling aerosols that it actually contributes a significant amount of cooling to the system. And biomass burning -- which occurs mainly as a result of tropical forest fires, deforestation, savannah and shrub fires -- emits large amounts of organic carbon particles that block solar radiation."

The intent of this study is to make the information about climate change more accessible and understandable. "We wanted to provide the information in a way that would be more helpful for policy makers," according to Nadine Unger, leader of the research team. "This approach will make it easier to identify sectors for which emission reductions will be most beneficial for climate and those which may produce unintended consequences."

No one should mistake the point of this study to indicate that coal burning and other power-generation and industrial processes are benign and therefore do not need to be scaled back. Although industrial processes mitigate their adverse effects with regard to global warming, the sulfates and aerosols that are beneficial in this one manner are responsible for a range of other, negative environmental impacts.

The paper was published online on Feb. 3 by the Proceedings of the National Academy of Sciences.

via: Worldchanging

Warmer ocean temperatures pose a serious threat to corals around the world.  Warmer waters typically kill the brown or green algae that a reef depends on for food, leading to bleaching and death of the reefs, but Penn State scientists have found some algae are not affected by rising temperatures, buying their coral partners some time.

Heat-resistant algae have been found in the Andaman Sea in the Indian Ocean as well as in spots in the Caribbean Sea and Pacific Ocean.  Scientists aren't sure if the resilient algae can save corals - the algae may not be able to be imported to coral reefs where it doesn't naturally occur and there are other things threatening coral, including rising ocean acidification, pollution and bottom-trawling fishing.  Considering all of that, the algae may be just a temporary life-preserver.

But some scientists think warmer waters may encourage the growth of these algae, benefitting the reefs they occupy over the long-term.  Continued research will be needed, but this discovery does offer a glimmer of hope for the world's coral.

via Dot Earth