• The most important news is that 196 countries approved the Paris Climate Accord Saturday afternoon (EST). Joby Warrick and Chris Mooney have summarized five things you should know about the agreement.
• Naomi Oreskes, coauthor of Merchants of Doubt, argues that in order to stop climate change the U.S. will have to give up on the idea that free markets alone can adequately address the problem and embrace a government-led plan of action. This is a compelling and beautifully written essay that raises many points worth considering; if you don’t have time to read the entire thing, at least read the last paragraph.
• In previous Weekly Roundups I have given links to articles calling into question the adequacy of the 2 degree C target and the use of “negative emissions” to achieve it. This week two articles appeared in scientific journals on those topics, one in Nature Geoscience and one in Nature Climate Change. Because of the expected impacts of a 2 degree C temperature increase on sea level rise, island nations are calling for limiting the temperature increase to 1.5 degrees C instead. Chris Mooney examines recent studies on the vulnerability of Antarctic and Greenland ice sheets to warming. A team of reporters from Carbon Brief interviewed scientists and others about the feasibility of a 1.5 degree C goal. This piece contains an interesting graphic showing how long we have before we use all of the carbon budget for a variety of temperature targets.
• Although most of us don’t often think about international shipping as a major source of CO2 emissions, it is currently responsible for 2-3%, and that number is likely to rise as nations cut back on their emissions. Consequently, there is a call for limitations on shipping emissions at the Paris Climate Summit. Henry Fountain of The New York Times analyzes what can be done to make ships more efficient.
• The buildings we live in make significant contributions to global warming through the energy required for heating/cooling, lighting, appliances, etc. How we build or retrofit them can have big impacts and best practices will be required to meet our climate goals.
• A California natural gas well is leaking methane to the atmosphere and by the time they get it stopped it is likely to have leaked as much greenhouse gas as a half-million cars would contribute in a year. You can see a video of the plume here. Meanwhile, a study of methane emissions from the Barnett Shale gas field in North Texas found that they are almost two times as large as estimated by the EPA Greenhouse Gas Inventory and 5.5 times the number from a separate global database.
• Global CO2 emissions during 2015 will decrease by 0.6% according to a study just published in Nature Climate Change. The projected decrease is attributable to a decrease in coal use in China.
• One hundred and fourteen large corporations have pledged to reduce their carbon emissions to a level consistent with keeping global warming below 2 degrees C. Currently, their cumulative emissions equal that of South Africa.
• A new study has found that up to a quarter of the near-surface permafrost in Alaska could thaw by 2100, releasing long-trapped carbon the atmosphere, exacerbating global warming.
• A paper published Monday in the Proceedings of the National Academy of Sciences provides a better evaluation of the disproportionate impacts of climate change on the poor. One finding is that estimates of the social cost of carbon have been too low. Another is that climate change will make it much harder for the poor to better their economic situation.
• A bipartisan group of leaders met in Norfolk on Wednesday to push for passage of the Virginia Coastal Protection Act in the 2016 General Assembly. This bill would generate about $250 million per year to invest in flood-protection measures, as well as energy efficiency, clean energy, and job training programs.
• NOAA announced Wednesday that this autumn (Sept. – Nov.) was the warmest on record for the contiguous U.S., with every state in the Lower 48 recording above average temperatures.
• A new paper reveals that nighttime temperatures have a major impact on respiration rates of trees in tropical rain forests. At night, plants use their internal sugars and other energy reserves to maintain cell function (respiration). This process acts the opposite of photosynthesis, meaning that CO2 is given off rather than taken up. It turns out that the rate of respiration at night depends strongly on the temperature, suggesting that trees might release more CO2 at night as Earth warms.
• A major storm (Storm Desmond) swept over parts of the U.K. last weekend, causing torrential rains that flooded more than 5000 homes and caused extensive damage. Using computer models scientists have estimated that the storm was made 40% more likely because of global warming.
• Matt Ridley is a self-proclaimed lukewarmer who has had a number of opinion pieces appear recently in such places as The Wall Street Journal and Scientific American. He recently was interviewed on BBC Radio 4 by Roger Harrabin, the BBC’s environment analyst. Carbon Brief sent a transcript of Ridley’s interview to eleven climate scientists and asked them to critique his claims. The annotated interview can be found here.

These news items have been compiled by Les Grady, member and former chair of the CAAV steering committee. He is a licensed professional engineer (retired) who taught environmental engineering at Purdue and Clemson Universities and engaged in private practice with CH2M Hill, the world’s largest environmental engineering consulting firm. Since his retirement in 2003 he has devoted much of his time to the study of climate science and the question of global warming and makes himself available to speak to groups about this subject. More here.