Articles

Decreasing oxygen in open ocean threatens biological diversity

Oxygen is fundamental to oceanic biological processes and its decline can cause major changes in ocean productivity and biodiversity. Over the past 50 years low oxygen zones in the open oceans have expanded by an area equivalent to half the size of Canada and hundreds of coastal sites now have low oxygen concentrations that limit the distribution and abundance of animal populations.

Greenhouse gas emissions from melting permafrost not yet significant

As the Earth warms, permafrost soils melt and this old carbon is released into the atmosphere as methane and CO2. Using radiocarbon dating of methane bubbles and soil organic carbon from lakes formed by melting thermafrost in Alaska, Canada, Sweden and Siberia combined with remote sensing it is found that methane and carbon dioxide releaed in the Arctic region during the past 60 years is much less than the CO2 contributed annually from anthropogenic and other sources.

Increase in extreme weather events confirmed by latest U.S. government report

There is strong evidence of marked changes in temperature extremes across the contiguous United States – extreme cold waves have become less common while extreme heat waves have become more common and heavy precipitation events in most parts of the United States have increased in both intensity and frequency. That is the conclusion of a report prepared by scientists from NOAA, NASA and other agencies.

Rapid Arctic warming connected to cooler winters in Northern mid-latitudes

A recent study presents evidence that regional warming over the Arctic Ocean can affect mid-latitude Northern Hemisphere continental weather. This study shows that there are two key Arctic regions where regional warming can induce distinguishable cold winters over northern continents. Warming over the Barents–Kara Sea region is likely to lead to East Asian cooling, whereas northern North America cooling is closely related to warming over the East Siberian–Chukchi Sea region.

Upward revision of methane emissions from shale gas production could erode natural gas’ cleaner energy advantage

Evidence that methane emissions from natural gas production have been considerably underestimated by the EPA was recently reinforced by the initiation of an investigation into how the EPA estimates methane emissions by the EPA’s Inspector General. If it is found that emissions of methane from natural gas production are considerably greater than current estimates, the advantage that natural gas has over coal will be eroded and the advantage of switching to natural gas as a cleaner form of energy diminished.

EC Perspective: Accounting for 800,000 years of climate change

Approximately 800,000 years ago something changed in the Earth’s climate system that led to the climate then following a series of approximately 100,000 year cycles. Small, predictable changes in the Earth’s orbit about the Sun act as triggers for the glacial and interglacial periods, but other factors such as ice sheet volume, CO2 concentration, and biological feedback mechanisms are also involved.