Sunset from Mauna Loa Observatory image courtesy of NOAA/Eric Johnson.

The National Oceanographic and Atmospheric Administration reported that for the first time the daily mean atmospheric concentration of carbon dioxide at the Mauna Loa Observatory was higher than 400 parts per million. The concentration of CO2 has grown at an increasing rate since the observatory began taking measurements in 1958. The concentration of CO2 is generally believed to be 40% higher than it was before the beginning of the Industrial Revolution. It may be higher now than at any other time in the last 3 million years. Because CO2 remains in the atmosphere for thousands of years, CO2 levels are not likely to drop naturally any time in the near future.

An international team of scientists wrote in Nature Geoscience that atmospheric CO2 concentrations twice pre-industrial levels would raise the average global temperature no more than 2 °C this century. That challenges the Intergovernmental Panel on Climate Change estimate that global temperatures could rise as much as 3 °C. The paper’s authors argue that the rate of global warming is slowing because the oceans have started to absorb more heat. But because the oceans’ ability to sequester heat is limited, they roughly agree with the IPCC’s finding that global temperatures could eventually rise as much as 4.5 °C.

The Arctic Monitoring and Assessment Program reported that arctic marine waters are acidifying rapidly as CO2 levels increase. The cold-water basin of the Arctic, which collects the runoff of northern rivers, is particularly susceptible to acidification. Recent estimates suggest the average acidity of the ocean surface worldwide is about 30% higher now than before the Industrial Revolution. If we were to stop emitting CO2 today, it would probably take thousands of years for the chemistry of the Arctic to return to pre-industrial levels.

An Environmental Research Letters paper surveyed the abstracts of nearly 12,000 peer-reviewed climate papers published from 1991 to 2011. The survey found that 97% of the papers that took a position agreed with the view that human activity is causing global warming. Just 2% of papers argued that human activity is not the cause of global warming, while 1% said that the cause of global warming is unclear. Charles Mann wrote in The Atlantic that thanks to huge reserves of methane hydrates we might not run out of fossil fuels any time soon. Although methane hydrates burn more cleanly than oil, Mann argued that switching to methane hydrates could be a disaster if it keeps us from investing in truly clean energy sources. In a response to Mann’s article, Amory Lovins argued that even with large methane hydrate reserves we are likely switch away from fossil fuels as renewable energy sources become cheaper and more competitive.

Nearly a third of commercial honey bee colonies in the US died or disappeared over the winter. Honey bee colonies have been dying off rapidly since 2006, raising concerns about whether there will be enough bees to pollinate crops. Scientists think that pesticides, mites, and malnourishment could all be factors in the bee deaths. The European Union recently restricted the use of neonicotinoid pesticides, which may play a role in killing bees. A study in PLoS One found that amphibian populations in the US are shrinking on average about 3.7% a year. The populations of more endangered amphibian species shrank at 11.6% a year. At those rates, amphibians will disappear from half their US habitats in just 20 years.

The UN High Representative for Disarmament Affairs called on NATO to develop a strategic plan for nuclear disarmament. Diplomats from the US, Russia, Egypt, and the Arab League expressed their support for a plan that would make the Middle East a “WMD-free zone”. Israel, which already has nuclear weapons, has said in the past that it doesn’t make sense to create such a zone until “peaceful relations exist for a reasonable time within the region.” The US said that it believes Syria has used the nerve agent sarin against rebel forces. Sarin is classified as a Schedule 1 toxic chemical under the Chemical Weapons Convention. President Obama warned Syria last year not to use chemical weapons.

North Korea took two Musudan missiles off launch-ready status and moved them away from the east coast of the Korean peninsula. Musudan missiles can carry a nuclear payload. With a theoretical range of up to 4,000 kilometers, the missiles could target not only South Korea and Japan, but might also be able to hit US bases in Guam. North Korea invited South Korean factory owners to discuss the reopening of its jointly-managed Kaesong Industrial Complex, but the South Korean government rejected the offer of talks.

Tunisia confirmed two cases of Middle East Respiratory Syndrome, which is caused by a novel coronavirus related to SARS. This is the first time the virus has been reported in Tunisia. Most of the known cases have been in Jordan, Saudi Arabia, Qatar, and the United Arab Emirates, but cases have also been confirmed in France, Germany, and the UK. The Tunisian cases are siblings in their thirties, whose father died of an unknown respiratory disease shortly after returning from a trip to Saudi Arabia and Qatar. So far 30 of the 49 people known to have contracted the disease have died.

Just one new case of the H7N9 bird flu has been reported since May 8. That suggests that the spread of the virus is at least temporarily slowing. Closing Chinese poultry markets seems to have been crucial in slowing the spread of the disease, since there is no clear evidence that H7N9 can be transmitted from person to person. China’s agriculture ministry estimated that responding to the flu cost its agricultural sector $6.5 billion. A Lancet paper identified a new subtype of the virus that is resistant to neuraminidase inhibitors like Tamiflu, which are widely used to treat the virus. The US government declared that the virus “poses a significant potential for a public health emergency” and authorized the use of genetic tests designed to screen for it. Novartis, Synthetic Genomics, the J. Craig Venter Institute and the Center for Disease Control began collaborating to produce a vaccine from the virus’ published gene sequence. CDC Director Thomas Frieden expressed concerns that budget cuts are affecting the World Health Organization’s ability to respond to the disease. And an op-ed in The Journal of the American Medical Association warned that there are serious practical and legal obstacles to producing and distributing vaccines quickly enough to be effective. There have been 132 confirmed cases of H7N9 and 37 deaths.

Ducks at a North Korean farm were discovered to have the H5N1 bird flu, which killed hundreds of people in a 2009 outbreak. More than 100,000 ducks were destroyed to prevent the disease from spreading. A Chinese team of scientists demonstrated in Science that they could mix genes from H5N1, which has a high mortality rate in humans, and the H1N1 swine flu, which is highly infectious, to produce hybrid viruses that can spread through the air among guinea pigs. It’s not clear whether the hybrid viruses would spread easily or have a high mortality rate in humans. But the Chinese team is being criticized for deliberating creating potentially dangerous viruses. “The record of containment in labs like this is not reassuring,” the UK’s former Chief Scientific Advisor Robert May said. “They are taking it upon themselves to create human-to-human transmission of very dangerous viruses. It’s appallingly irresponsible.”

This news summary was put together in collaboration with and is cross-posted at Anthropocene. Thanks to Seth Baum, Kaitlin Butler, and Grant Wilson for help compiling the news.

You can help us compile future news posts by putting any GCR news you see in the comment thread of this blog post, or send it via email to Grant Wilson (grant [at] gcrinstitute.org).