Ocean acidification may threaten food security

Alister Doyle in Environment News Network via Reuters: Acidification of the seas linked to climate change could threaten fisheries production and is already causing the fastest shift in ocean chemistry in 65 million years, a U.N. study showed on Thursday. Production of shellfish, such as mussels, shrimp or lobsters, could be most at risk since they will find it harder to build protective shells, according to the report issued on the sidelines of U.N. climate talks in Mexico.

It could also damage coral reefs, vital as nurseries for many commercial fish stocks. "Ocean acidification is yet another red flag being raised, carrying planetary health warnings about the uncontrolled growth in greenhouse gas emissions," said Achim Steiner, head of the U.N. Environment Program (UNEP).

"Whether ocean acidification on its own proves to be a major or a minor challenge to the marine environment and its food chain remains to be seen," he said in a statement. A UNEP booklet reviewing scientific findings about ocean acidification, caused by water soaking up greenhouse gases from the atmosphere, said that it adds to threats to food security that already include overfishing and pollution….

Jakob van Ruisdael's "Rough Sea at a Jetty," from 1650

Uncertain levees and the aftermath of Hurricane Katrina

Matthew Cardinale in IPS: Today, the population of New Orleans is still about 175,000 people fewer than it was before Hurricane Katrina hit four years ago next month. Along with concerns about jobs and housing costs, the city's vulnerability to flooding has weighed heavily on the minds of many evacuees, many of whom have not returned.

In the first part of this series, IPS explained how the levees are being built up to a new standard of protection - essentially 99 percent protection each year - scheduled to be completed by the end of 2011, and that Holland, by comparison, uses a higher standard of 99.99 percent protection.

Unfortunately, most New Orleanians, both current residents and in the diaspora, have very little understanding of what level of protection is being promised. Neither the local nor national media have asked the tough questions, said Sandy Rosenthal, executive director of Levees.org.

People in New Orleans see work being done on the levees, but they generally sense that the level of protection being promised would not be strong enough to handle another hurricane on the scale of Katrina. The street wisdom is that the new levees might be strong enough for a Category 3 or 4 hurricane, but certainly not a 5.

In reality, the scale which measures hurricanes in categories 1 through 5, the Saffir-Simpson scale, speaks to intensity or wind speed, not to flood levels, the latter of which are more important to the issue of levee protection, several experts told IPS. Ed Link of the Interagency Performance Evaluation Task Force, which studied the Hurricane Katrina levee failures, said the scientific community is debating whether to create a new category system that is both meaningful and that people can understand. He declined to identify a category level which would describe the level of protection, using Saffir-Simpson, that would be offered by the new levees....

New Orleans flooded by Hurricane Katrina in 2005

Revealed: the secret evidence of global warming Bush tried to hide

Suzanne Goldenberg and Damian Carrington in the Guardian (UK): Graphic images that reveal the devastating impact of global warming in the Arctic have been released by the US military. The photographs, taken by spy satellites over the past decade, confirm that in recent years vast areas in high latitudes have lost their ice cover in summer months.

The pictures, kept secret by Washington during the presidency of George W Bush, were declassified by the White House last week. President Barack Obama is currently trying to galvanise Congress and the American public to take action to halt catastrophic climate change caused by rising levels of carbon dioxide in the atmosphere.

One particularly striking set of images - selected from the 1,000 photographs released - includes views of the Alaskan port of Barrow. One, taken in July 2006, shows sea ice still nestling close to the shore. A second image shows that by the following July the coastal waters were entirely ice-free.

The photographs demonstrate starkly how global warming is changing the Arctic. More than a million square kilometres of sea ice - a record loss - were missing in the summer of 2007 compared with the previous year.

…The latest revelations have triggered warnings from scientists that they no longer have the funds to keep a comprehensive track of climate change. Last week the head of the US's National Oceanic and Atmospheric Administration (NOAA), Professor Jane Lubchenco, warned that the gathering of satellite data - crucial to predicting future climate changes - was now at "great risk" because America's ageing satellite fleet was not being replaced….