Study: Half a Degree Matters

The Nicholas Institute for Environmental Policy Solutions at Duke University
The Nicholas Institute for Environmental Policy Solutions at Duke University

Last week more than 150 nations signed the Paris Agreement, pledging to hold the increase in the global average temperature to well below 2 degrees Celsius above pre-industrial levels and to pursue efforts to limit the temperature increase to 1.5 degrees Celsius. Now, the first comprehensive analysis of the impacts of that half centigrade difference has been published in the journal Earth System Dynamics. The scientists found the additional 0.5 degrees Celsius would lead to longer heatwaves—“the difference between events at the upper limit of present-day natural variability and a new climate regime”—as well as more severe droughts and, in the tropics, decreased crop yield and the potential demise of all coral reefs. The extra 0.5 degrees Celsius could also mean that global sea levels rise 10 centimeters more by 2100.

“We found significant differences for all the impacts we considered,” says the study’s lead author Carl Schleussner, a scientific advisor at Climate Analytics in Germany.

The researchers analyzed climate models used in the Intergovernmental Panel on Climate Change Fifth Assessment Report, which focused on the projected regional impacts of 1.5 degrees Celsius and 2 degrees Celsius of warming, and considered 11 indicators, including extreme weather events, water availability, crop yields, coral reef degradation and sea-level rise.

They found that projected climate impacts at a 2 degrees Celsius increase are significantly more severe than at a 1.5 degrees Celsius increase in some regions. In the Mediterranean, for example, fresh-water availability by 2100 would be some 10 percent lower in a 1.5 degrees Celsius world and 17 percent lower in a 2 degrees Celsius world. In Central America and West Africa, the half-degree difference could reduce maize and wheat yields by twice as much. Tropical regions would bear the brunt of the impacts of an additional half degree of warming, experiencing heat waves at about twice the global rate. Those events could last up to three months at 2 degrees Celsius, compared with two months at 1.5 degrees Celsius, the researchers say.

Tropical coral reefs are particularly sensitive to the half degree increase. By 2100, some reefs might adapt to 1.5 degrees Celsius of warming, but the larger increase would put nearly all of them at risk of severe degradation from coral bleaching.

EPA Moves Forward with Clean Energy Incentives Program

The U.S. Environmental Protection Agency (EPA) has sent a proposal on the Clean Energy Incentive Program (CEIP), an optional program included in the Clean Power Plan that rewards states for early investment in certain renewable energy or energy efficiency projects in 2020 and 2021, to the Office of Management and Budget for review. The move is the final step before the CEIP can be formally proposed to the public (subscription).

The EPA released details on the draft CEIP as part of the final Clean Power Plan—the Obama administration’s rule to limit greenhouse gas emissions from the existing fleet of fossil fuel-fired power plants—in August. But, earlier this year, the Supreme Court issued a stay of the Clean Power Plan.

“Many states and tribes have indicated that they plan to move forward voluntarily to work to cut carbon pollution from power plants and have asked the agency to continue providing support and developing tools that may support those efforts, including the CEIP,” the EPA said. “Sending this proposal to OMB for review is a routine step and it is consistent with the Supreme Court stay of the Clean Power Plan.”

Pleasant Weather Affecting Americans’ View of Climate Change

A new study in the journal Nature finds that 80 percent of Americans live in counties where the weather is more pleasant than four decades ago. This mild temperature trend, the study says, is increasingly preferred, lessening many Americans’ concern about climate change.

“Rising temperatures are ominous symptoms of global climate change, but Americans are experiencing them at times of the year when warmer days are welcomed,” said study co-author Patrick J. Egan, an associate professor at New York University’s Wilf Family Department of Politics. He adds that “whereas weather patterns in recent decades have served as a poor source of motivation for Americans to demand a policy response to climate change, public concern may rise once people’s everyday experiences of climate change effects start to become less pleasant.”

Conducted by New York and Duke universities, the study examined each county in every U.S. state from 1974 to 2013—assessing the mildness of winters, rainfall averages, and humidity and heat intensity during summer months. It found that 99 percent of Americans live in places where the average January temperature increased.

“Here in the U.S., when we’re experiencing ice storms, the idea of a 1.5 or 2 degree rise might sound like good news,” said Megan Mullin, associate professor of environmental politics at Duke University. As a result, she said, scientists need to reconsider their messages.

The Climate Post offers a rundown of the week in climate and energy news. It is produced each Thursday by Duke University’s Nicholas Institute for Environmental Policy Solutions.

Nations to Sign Paris Climate Agreement Friday

The Nicholas Institute for Environmental Policy Solutions at Duke University
The Nicholas Institute for Environmental Policy Solutions at Duke University

Four months after it was finalized by delegates to the Paris Climate Change Conference, the Paris Agreement will be signed by more than 100 nations on Friday. While the agreement is facially insufficient to meet its overall emissions objectives, the signing of the Paris agreement nevertheless is significant. It brings into effect the approach and policy infrastructure needed to tackle the United Nations Framework Convention on Climate Change’s ambitious goal to minimize human-caused climate change. The agreement does not solve the problem on its own, but it is a structured revisitation of the science and national commitments that provide the adaptive approach necessary to reach a solution. It is now on researchers and entrepreneurs to invent solutions; for governments, development banks and the private sector to deploy them; and for nations to hold each other accountable as this agreement goes into effect.

Energy innovation is just one of the benefits of the signing, according to White House Press Secretary Josh Earnest.

“This will open up a market for energy innovation that U.S. companies have pioneered,” Earnest said. “This is going to open up a global market for the kind of renewable energy technology that U.S. companies are at the cutting edge of.”

Other shifts have occurred since the Paris Agreement was finalized, GreenBiz reports. Big companies have backed the Clean Power Plan, there’s a rise in “sub-national” climate action at the state and city level and President Obama has proposed $10-a-barrel-tax on oil, they say.

EPA Finds Benefits Outweigh Cost of Mercury Rule

Benefits of the Mercury and Air Toxics Standard (MATS) rule outweigh cost, the U.S. Environmental Protection Agency (EPA) said in findings released in defense of its issuance of the first-ever federal regulations requiring power plants to cut mercury emissions and other toxics.

The Supreme Court found, last year, that the EPA should have considered compliance costs when determining whether it was “appropriate and necessary” to regulate mercury emissions from the power sector. In a June ruling, it did not strike down the regulation; rather, it required the EPA to take costs into consideration.

In its final 167-page report on the matter, now awaiting publication in the Federal Register, the EPA details how it considered cost in evaluating whether to regulate coal-and oil-fired power plants under the Clean Air Act (subscription).

“Based on this analysis, EPA has determined that the cost of complying with MATS, whether assessed as a percentage of total capital expenditures, percentage of power sector sales, or predicted impact on the retail price of electricity, is reasonable and that the electric power industry can comply with MATS and maintain its ability to provide reliable electric power to consumers at a reasonable cost,” the EPA wrote.

The annual cost of complying with MATS, the EPA found, amounts to between 2.7 and 3.5 percent of electricity sales, and the capital costs between 3 and 5.9 percent of annual power sector capital expenditures over 10 years.

Methane Emissions Greater Than Thought

In its newly released annual greenhouse gas emissions inventory, the EPA raised its estimate of total U.S. methane emissions in 2013 by 13 percent—an increase of more than 3.4 million metric tons and a long-term global warming impact of a year’s worth of emissions from some 20 million cars, Science News reported. The agency’s first estimate of methane emissions for 2014 is even higher, although only slightly so—29.233 million metric tons compared with 28.859 million metric tons.

Although there was a roughly 1 percent increase in total U.S. greenhouse gas emissions between 2013 and 2014, the inventory shows 2014 levels were 8.6 percent lower than 2005 levels, taking into account carbon sinks (subscription).

According to the EPA, the biggest methane emitter is the oil and natural gas industry—not animals like cattle and other livestock, as had been suggested by last year’s inventory. The data in this latest inventory are based on new techniques for estimating methane leaking from valves, compressors, vents, and other oil and gas equipment.

The Climate Post offers a rundown of the week in climate and energy news. It is produced each Thursday by Duke University’s Nicholas Institute for Environmental Policy Solutions.

Climate-Change-Related Precipitation Extremes Hard to Predict

The Nicholas Institute for Environmental Policy Solutions at Duke University
The Nicholas Institute for Environmental Policy Solutions at Duke University

Scientists have warned that severe drought and precipitation are among the risks of greenhouse-gas-induced climate change, but a study published in the journal Nature finds that extremely warm temperatures do not always translate into record wet and dry extremes. Highlighting the complexities in predicting the effects of planetary warming on precipitation, lead author Fredrik Ljungqvist of Stockholm University said that more dramatic wet-dry weather extremes had occurred in centuries cooler than the 20th century.

“Several other centuries show stronger and more widespread extremes,” he said. “We can’t say it’s more extreme now.”

In this first hemispheric-scale, centuries-long water availability assessment, the researchers statistically analyzed evidence for changes in precipitation and drought, compiling hundreds of precipitation records across the Northern Hemisphere from historical accounts as well as archives on such things as tree-rings and lake sediments.

They detected a pattern of alternating moisture regimes throughout the last 12 centuries, suggesting that “the instrumental period is too short to capture the full range of natural hydroclimate variability.”

Their finding that the last century’s temperature rise may not have affected the hydroclimate as much as previously thought challenges the conclusions of the United Nations Intergovernmental Panel on Climate Change.

In a News and Views article published in Nature, Matthew Kirby of California State University at Fullerton suggested that current climate models should not be discarded because their results, which indicate that “dry gets dryer and wet gets wetter,” do not match the Ljungqvist team’s proxy results, which indicate no difference in the water dynamics of the 20th century and those of the pre-industrial era.

“Do their results invalidate current predictive models?” Kirby asked. “Certainly not. But they do highlight a big challenge for climate modellers, and present major research opportunities both for modellers and for climate scientists who work with proxy data.”

Study: Climate Change Causing Earth to Shift

A study published in the journal Science Advances reveals that climate change affects how Earth tilts on its axis. Although scientists have known that Earth’s spin axis has been drifting due to ice cap melt in Greenland and Antarctica, the new research suggests that changes in terrestrial water storage also play a role in the planet’s decadal axis swings. The finding is based on data collected from NASA’s Gravity Recovery and Climate Experiment (GRACE) satellite, which can detect changes in the mass of Earth’s ice sheets and oceans.

Before 2000, Earth’s spin axis was moving westward toward Canada, but since then, climate-change-driven ice loss has pulled the direction of drift eastward approximately seven inches a year—a shift that lead researcher Surendra Adhikari of NASA’s Jet Propulsion Laboratory described as “very dramatic” and that scientists say is meaningful.

“This is the first time we have solid evidence that changes in land water distribution on a global scale also shift which direction the axis moves to,” said Adhikari.

Although the study data doesn’t indicate whether the most recent shift in the pole is the result of human activities, the study authors think they will be able to use them to tease out man-made climate change later this year. Because polar motion and climate variability appear to be linked, scientists can examine historical records of the pole’s motion in relation to changes in Earth’s climate. If those changes are less dramatic than the ones evidenced today, scientists could assert that global warming has a controlling influence on Earth’s poles.

U.N. Climate Agreement Terms Studied, Launch Pegged Early

Next week on Earth Day (April 22), 130 countries are expected to sign the Paris Climate Agreement, which has a goal of limiting average surface temperatures to “well below” 2 degrees Celsius. But already the United Nations Intergovernmental Panel on Climate Change is looking into the feasibility of what U.N. Climate Chief Christiana Figueres describes as “a moonshot”: limiting global emissions to 1.5 degrees Celsius.

Figueres believes the Paris agreement will take effect in 2018—two years sooner than currently slated.

The agreement will come into force once 55 parties representing 55 percent of the world’s total emissions have both signed and ratified it.

The Climate Post offers a rundown of the week in climate and energy news. It is produced each Thursday by Duke University’s Nicholas Institute for Environmental Policy Solutions.

Antarctic Ice-Sheet Collapse Could Trigger Rapid Sea-Level Rise

The Nicholas Institute for Environmental Policy Solutions at Duke University
The Nicholas Institute for Environmental Policy Solutions at Duke University

A study published in Nature finds that Antarctic ice-sheet collapse driven by greenhouse gas emissions could double the sea-level rise predicted for this century—from 3.2 feet according to a three-year-old United Nations estimate to upward of 6.5 feet by 2100. The research builds on the work of other recent studies pointing to an irreversible melting of the West Antarctic Ice Sheet as a result of human-caused climate change, but it suggests that sea-level rise could shift into high gear, becoming an existential problem for low-lying coastal cities within the lifespan of current generations of people absent rapid emissions cuts to contain warming to within 2 degrees Celsius above pre-industrial levels.

The study findings are based on new computer simulations showing that warming of the atmosphere and the oceans makes the ice sheet vulnerable from above and below. By the 2050s, according to the simulations, the ice sheet would begin disintegrating, and parts of the higher, colder ice sheet of the East Antarctica would also eventually fall apart.

The climate model developed by the study authors accounts for ice loss through complex processes, including “hydro fracturing,” a process whereby meltwater on ice shelves causes huge chunks of ice to fall into the water. By reflecting these processes, the researchers were able to simulate past geological periods in which sea levels were higher than today but carbon dioxide levels were about the same or even much lower. They projected sea-level rise using versions of their model that best simulated these periods—the first model to do so.

Why is reconstruction of past rises in sea level important? High sea levels during warm intervals, such as the Pliocene and Eemian eras, imply that the Antarctic Ice Sheet is highly sensitive to climate warming.

“In the past, when global average temperatures were only slightly warmer than today, sea levels were much higher,” said study co-author Rob DeConto, a geoscientist at the University of Massachusetts Amherst. “At the high end, the worst-case scenarios, with sort of business as usual greenhouse gas emissions … we will literally be remapping coastlines. North America is kind of a bull’s eye for impacts of sea level rise if it’s the west Antarctic part of Antarctica that loses the ice first. That’s the place that we’re worried about losing ice first.”

Study: Health Impacts of Climate Change Significant

The public health impacts of climate change on people in the United States will be significant and wide ranging, according to a study by the U.S. Global Change Research Program. The study reflects data and analysis from eight agencies, led by the U.S. Environmental Protection Agency (EPA), the Department of Health and Human Services, and the National Oceanic and Atmospheric Administration, which said that “Nearly all of the health threats, from increases in our exposure to excessive heat to more frequent, severe or longer-lasting extreme weather events to degraded air quality to diseases transmitted through food, water, and vectors (such as ticks and mosquitoes)—even stresses to our mental health—are expected to worsen.”

Without rapid efforts to combat climate change, extreme heat alone will cause more than 11,000 additional deaths in the summer of 2030, the study suggests. Other risks include worsening allergy and asthma conditions and increased exposure of food to certain pathogens and toxins. But climate change will not just exacerbate existing risks—it will give rise to unprecedented health problems such as the spread of Lyme disease in new locations.

“Every American is vulnerable to the health impacts associated with climate change,” said White House Science Adviser John Holdren, adding that “Some are more vulnerable than others.”

These groups include pregnant women, children, the elderly, low-income people, communities of color and those with disabilities or pre-existing medical conditions.

Release of the findings coincided with the Obama administration’s announcement of several new initiatives to address those impacts, such as expanding the scope of a presidential task force on childhood risks to include climate change (subscription). Other actions include creating climate change and health curricula for schools and establishing a Climate-Ready Tribes and Territories Initiative, which will provide funding for prevention of climate-change-related health problems.

Paris Deal: Largest Polluters Agree to Sign

Last week, the White House announced that the United States and China will sign the Paris Agreement to combat global climate change at a United Nations ceremony April 22.

“Our cooperation and our joint statements were critical in arriving at the Paris agreement, and our two countries have agreed that we will not only sign the agreement on the first day possible, but we’re committing to formally join it as soon as possible this year,” said President Obama. “And we urge other countries to do the same.”

Brian Deese, senior adviser to President Obama, said swift approval of the agreement would keep emissions reductions efforts on track. Noting congressional action last year to extend tax credits for wind and solar energy and asserting firm legal ground for the Clean Power Plan, Deese said that the United States has both “the capacity and the tools” to meet its international commitments.

United Nations Secretary-General Ban Ki-moon has said that he expects at least 120 countries will sign the agreement at the April 22 ceremony at the U.N.’s New York headquarters. To enter into force, that agreement needs at least 55 countries representing at least 55 percent of global emissions to formally accede to it. So far, three Pacific island nations have ratified the deal.

The Climate Post offers a rundown of the week in climate and energy news. It is produced each Thursday by Duke University’s Nicholas Institute for Environmental Policy Solutions.