On Monday California Governor Jerry Brown and legislative leaders released a plan to extend through 2030 the state’s cap-and-trade program, which limits carbon emissions and requires polluters to buy allowances for greenhouse gas emissions—that is, permits to pollute. The deal updates how carbon emitters can use pollution allowances and offsets, empowers the California Air Resources Board to set a price cap on permits, and prevents local air districts from placing additional carbon emissions restrictions on polluters already regulated under the cap-and-trade program. A vote on Assembly Bill 398 and AB 617, a companion bill to increase local air pollution monitoring and pollution penalties, could come as early as today; the former will need approval of two-thirds of the Senate and Assembly.
The deal represents a difficult—and some say, imperfect—balancing of environmental and business interests.
The deal’s price cap provision is meant to guard against energy price spikes, but there are concerns it might undermine the purpose of limiting emissions. Thus far, permit prices have hovered near the program’s price floor and emissions have been within the state’s targets, but if demand spikes and prices hit the ceiling, emissions could rise. The proposal includes provisions to ensure that emissions goals are still met when the price ceiling is hit.
The offsets provision would decrease the amount of emissions reductions businesses can achieve through environmental projects in other sectors, and it would require that half of such projects be sited in California. Industry and environmental justice groups have sparred over the offsets, because although they can be a potentially cheaper alternative to achieving emissions reductions at regulated sources they are often without benefit to local air quality.
The two camps also do not see eye to eye on the number of free emissions allowances businesses should receive to keep them from being disadvantaged against out-of-state competitors not subject to the cap-and-trade program. In the deal announced Monday, companies will continue to receive free allowances, though the total number of allowances will shrink as the emissions cap is lowered to meet the state’s goal of cutting greenhouse gas emissions to 40 percent below 1990 levels by 2030.
The deal prioritizes state programs that could receive allowance auction proceeds. First in line: efforts to control toxic air pollution from mobile or stationary sources, followed by low-carbon transportation projects and sustainable agriculture programs.
Nine northeastern states are contemplating the future of their own cap-and-trade program. Since inception of the Regional Greenhouse Gas Initiative (RGGI) in 2008, the states’ aggregate emissions have decreased 37 percent—spurred in part by the cheap cost of natural gas (subscription). But RGGI advocates say that the program hasn’t sent electric bills soaring; instead, electricity costs have fallen 3.4 percent, again with help from natural gas prices. The program is set to release a plan for reducing the region’s carbon cap later this year, and there are signs that New Jersey may rejoin the program and that Virginia may link up with it—an expansion with both symbolic and market significance.
G20 Meeting Highlights Rift with the United States Over Its Climate Change Stance
Last week’s G20 meeting in Hamburg concluded with leaders of 19 nations renewing their pledge to implement the Paris Agreement and German Chancellor Merkel reiterating those nations’ consensus that “the Paris agreement is irreversible.”
Negotiations over the wording of the final communiqué from Germany hit a snag when the United States insisted on a line that read, “USA will endeavor to work closely with other partners to help their access to and use of fossil fuels.” The final language reads, “The United States of America states it will endeavour to work closely with other countries to help them access and use fossil fuels more cleanly and efficiently and help deploy renewable and other clean energy sources, given the importance of energy access and security in their nationally-determined contributions.”
The G20 declaration noted the U.S. withdrawal from the accord but said that the United States affirmed its “strong commitment to an approach that lowers emissions while supporting economic growth and improving energy security needs.” The U.S. exit from the accord will become official in November 2020—the year of the next presidential election.
Regarding climate change mitigation, Inside Climate News laid out “six degrees of U.S. isolation” from the other G20 members: the need for increased ambition, the economic benefits of climate action, the coming energy transformation, the need for international finance, the need to end inefficient fossil fuel subsidies, and the vestigial role for fossil fuels.
On Tuesday, the Trump administration appointed a renewable energy critic and former spokesman for a Koch Industries-funded campaign promoting fossil fuels to the post of senior adviser in the U.S. Department of Energy’s Office of Energy Efficiency and Renewable Energy.
Study Offers Bad News on Extreme Flooding, Good News on Planning for That Phenomenon
A new study published Tuesday in Nature Communications suggests that extreme flooding currently expected to occur on average once every 100 years could, by 2050, occur every decade or even every year along the world’s vulnerable coastlines. The good news? Use of newly available data and advanced models offers the promise of improving global predictions of extreme sea levels.
“Up to 310 million people residing in low elevation coastal zones are already directly or indirectly vulnerable to ESL”—or extreme sea levels—“and coastal storms are causing damages in the order of tens of billions of dollars per year,” said the researchers. “These numbers could increase dramatically with SLR”—or sea-level rise—“and other changes, leading to annual damages of up to almost 10% of the global gross domestic product in 2100 if no adaptation measures are taken.”
As the climate changes, according to the study, category I hurricanes could do the same amount of damage as category II or III hurricanes did when sea levels were lower. But extreme sea levels, which often arise from a combination of high tides and storm surges, are often underrepresented in high-profile climate change documents such as those of the Intergovernmental Panel on Climate Change. To quantify the uncertainty of current extreme sea-level estimates, the study used newly released tide gauge data to conduct a meta-analysis of some 20 advanced climate models and found that predicted flood rates were underestimated for the West Coast of North and South America as well as for southern Europe and Australia.
According to researchers, including extreme sea levels in coastal impact studies is vital to helping vulnerable areas to protect themselves.
Democrats and Republicans are sharply divided on climate change in Congress but perhaps not so much at the municipal level. In a show of bipartisan support for the Paris Agreement and the Clean Power Plan at the conclusion of the U.S. Conference of Mayors in Miami Beach on Monday, leaders from more than 250 cities voted on symbolic resolutions calling for the Trump Administration to rejoin the global climate accord and embracing the goal of running their jurisdictions entirely on renewable energy by 2035. Another resolution called for President Trump and Congress to “develop a comprehensive risk management program to address future flood risks from sea level rise.”
“I think most mayors in America don’t think we have to wait for a president” whose beliefs on climate change are not supported by science, said New Orleans Mayor Mitch Landrieu. “There’s near unanimity in this conference that climate change is real and that humans contribute to it,” he said, adding “If the federal government refuses to act or is just paralyzed, the cities themselves, through their mayors, are going to create a new national policy by the accumulation of our individual efforts.”
The mayors showcased climate change with panels on climate resiliency and a neighborhood tour by Miami Mayor Philip Levine highlighting municipal efforts to cope with sea-level rise. Miami Beach is one of the U.S. cities most vulnerable to climate change.
Preliminary results of a survey jointly conducted by the U.S. Conference of Mayors (USCM) and the Center for Climate and Energy Solutions were released at the conference on Saturday. According to USCM, the survey of 66 municipalities, ranging from 21,000 to 8.5 million residents across 30 states, found “overwhelming interest by cities in collaborating with the private sector to accelerate climate efforts.”
On Tuesday at a Senate appropriations subcommittee hearing, U.S. Environmental Protection Agency (EPA) head Scott Pruitt suggested that the Clean Air Act may not have given his agency the tools for those efforts, telling committee members that the EPA’s endangerment finding, which established that greenhouse gas emissions were harmful to human health, did not settle the question of how the agency should regulate those emissions.
“Massachusetts v. EPA simply said to the EPA that it had to make a decision on whether it had to regulate, whether it posed a risk to health, and there was an endangerment finding that followed that in 2009. It did not address whether the tools were in the toolbox,” Pruitt said. He added, “I think what’s important is that we are responding to the CO2 issue through the regulation of mobile sources, we’re also evaluating the steps or the tools we have in the toolbox with respect to stationary sources, and that’s our focus,” he said.
Challenging Pruitt’s assertion that the Clean Air Act gave the EPA no clear authority to regulate carbon emissions, John Walke, clean air director at the Natural Resources Defense Council, pointed to two Supreme Court cases—American Electric Power Co. v. Connecticut and Utility Air Regulatory Group v. EPA—affirming that authority, specifically with regard to emissions from stationary sources.
Global Sea-Level Rise Accelerates
A new study, published Monday in the journal Nature Climate Change, adds to recent literature confirming an acceleration in sea-level rise during the past few decades. That literature, which includes a study published in early June that found a tripling of the rate of sea-level increase between 1990 and 2012, is significant in part because of earlier uncertainty about whether global waters were indeed rising—uncertainty cited by climate change deniers. Specifically, the new study reveals the close match between what scientists know about contributors to sea-level rise and measured rates from satellites, and it nails down the sea-level rise acceleration.
The study led by Xianyao Chen of the Ocean University of China and Qingdao National Laboratory of Marine Science and Technology showed that the main contributor to recent sea-level rise is the thawing of Greenland’s ice sheet. The study found that the annual rate of sea-level rise had reached 0.13 inches in 2014. But ocean levels rose 50 percent faster in 2014 than in 1993, with meltwater from the Greenland ice sheet making up 25 percent of total sea level increase compared with 5 percent 20 years earlier. That finding suggests that the rate will continue to accelerate, and scientists say oceans are likely to rise about three feet by century’s end.
The study co-authors said the rate’s acceleration “highlights the importance and urgency of mitigating climate change and formulating coastal adaptation plans to mitigate the impacts of ongoing sea level rise.”
Climate Change-Related Fires Increase in the Arctic
Recent massive fire years in Alaska and Canada have been driven by extreme lightning storms that are likely to move north with climate warming, according to findings in Nature Climate Change by researchers from Vrije Universiteit Amsterdam and the University of California, Irvine. The scientists found that as fires creep northward, near the transition from boreal forests to Arctic tundra, large amounts of carbon currently locked in permafrost could be released. In addition, trees could begin growing in the tundra, darkening surfaces previously covered with snow, which prevents the reflection of sunlight away from Earth and contributes to global warming.
Using satellite and ground-based data, the researchers discovered that lightning-caused fires have risen 2 to 5 percent a year for the last four decades. The reason? Warmer temperatures increase thunderstorms, which in turn increase lightning and fire risk. These changes are part of a complex climate feedback loop, said Sander Veraverbeke of Vrije Universiteit Amsterdam, the study’s lead author.
“You have more fires; they creep farther north; they burn in these soils which have a lot of C02 and methane that can be exposed directly at the moment of the fire and then decades after,” Veraverbeke said. “That contributes again to global warming; you have again more fire.”
The study was prompted by immense fires in Alaska and Canada’s Northwest Territories in two of the last three years. Lightening was the cause of some 82 percent of the burned areas in the Northwest Territories in 2014 and 95 percent of the burned areas in Alaska in 2015—areas that don’t usually experience fires, according to Veraverbeke.
“These fires are claiming an area that they haven’t burned historically, which also means they can change the carbon balance and shift an ecosystem into a different state,” Veraverbeke said.
On Tuesday the Trump administration released its proposed fiscal 2018 budget, which detailed deep cuts to energy and environmental programs—cuts telegraphed by the White House’s budget outline in March. The reductions at the U.S. Environmental Protection Agency (EPA) and the Energy and Interior departments were defended by Office of Management and Budget Director Mick Mulvaney as necessary to boost Pentagon accounts and leave Social Security untouched at hearings with the House and Senate Budget committees yesterday and today, respectively.
In broad strokes, the budget calls for a 31 percent cut for the EPA, an 11 percent cut for the Interior Department, and an almost 6 percent cut for the Energy Department.
The EPA cuts, outlined in budget documents obtained on Monday by the National Association of Clean Air Agencies, include zeroing out of some programs and significantly reduced funding for research into climate change. Some of the EPA cuts would
- Reduce science and technology funding by nearly 40 percent to $450 million.
- Cut grants to states for their own air and other environmental protections from $3.6 billion to $2.9 billion.
- Remove all $19 million in aid for Alaskan native villages under threat from warming temperatures and rising sea levels.
- Scrap the $8 million used to fund the greenhouse gas reporting program, which lists carbon emissions from industrial facilities.
“During the previous administration the pendulum went too far to one side where we were spending too much of your money on climate change and not very efficiently. We don’t get rid of it here. Do we target it? Sure. Do a lot of the EPA reductions aim at reducing the focus on climate science? Yes. Does it mean we are anti-science? Absolutely not,” Mulvaney said on Tuesday.
At the Energy Department, the Trump administration would slash funding for clean energy programs, power grid operations and next-generation energy technologies, reversing years of collaboration with the private sector and academia to advance clean energy transmission and reliability, smart grid research and development, and energy storage (subscription). Some of the Energy Department cuts would
- Halve the budget of the Office of Energy Efficiency & Renewable Energy, which oversees efficiency standards for buildings and appliances, supports research in clean energy technologies, and provides the majority of funding for the National Renewable Energy Laboratory. Weatherization and state energy subprograms are targeted for elimination.
- Gut cutting-edge technology, leaving just $20 million to close out the Advanced Research Projects Agency-Energy and cutting fossil research and development funding by more than half—funding that supports research on carbon capture and sequestration and the National Energy Technology Laboratory.
- Decrease funding for the Office of Nuclear Energy by about a third.
- Decrease funding for the Office of Science, which oversees the majority of the national energy labs, from $5.3 billion to $4.5 billion.
At the Interior Department, the Trump administration would significantly reduce new federal land acquisitions and revenue-sharing partnerships with states, but pursue new oil and drilling opportunities in the Arctic National Wildlife Refuge starting in 2022. One of the Interior Department cuts would repeal payments to counties that produce geothermal energy as an alternative heat and energy source.
The president’s proposed budget is likely to face considerable pushback from Congress. “Almost every president’s budget proposal that I know of is basically dead on arrival,” Senator John Cornyn told CNN just hours before the budget release.
Court Suspends Litigation on Methane Leaks Rule
Last week, the U.S. Court of Appeals for the District of Columbia Circuit for the foreseeable future paused litigation over the Obama administration’s curbs on methane—a short-lived greenhouse gas that is more potent than carbon dioxide—for new oil and gas operations. The court granted the Trump administration’s request to hold the litigation in abeyance (subscription) in the wake of a March “energy independence” executive order, which required the U.S. Environmental Protection Agency to review the new source methane standards, along with other Obama administration actions to address climate change.
The ruling came a week after the U.S. Senate rejected a resolution to repeal a 2016 Bureau of Land Management methane rule, which limits venting, flaring, and equipment leaks at more than 100,000 oil and gas wells on public and tribal lands across the West.
In light of the Senate’s failure to kill that rule, the American Petroleum Institute (API) last week asked Interior Secretary Ryan Zinke to postpone compliance with it (subscription). In a letter to Zinke, API urged that compliance dates for the methane and waste prevention rule be pushed off for two years. Industry and states are challenging the rule in court, and the Trump administration has promised to review it (subscription).
Study: Sea-level Rise Not Just Under Way—It’s Accelerating
The pace of sea level rise has nearly tripled since 1990, due largely to an acceleration in the melting of ice sheets in Greenland and Antarctica, according to a new study, which detected a larger rate of increase than previous studies by taking a new approach to handling of pre-satellite data. Overall, the new reconstruction of sea-level rise is similar to that of other researchers except for the reconstruction during the early 1900s, when it shows ocean levels rising at a slower pace. Consequently, it shows a faster acceleration of sea-level rise over recent decades.
The study in the Proceedings of the National Academy of Sciences concludes that before 1990, oceans were rising at about 1.1 millimeters per year, or just 0.43 inches per decade. But from 1993 through 2012, it finds that they rose at 3.1 millimeters per year, or 1.22 inches per decade.
Last week, a group of scientists, including three working for the U.S. Geological Survey (USGS), published a paper that highlighted the link between sea-level rise and global climate change, arguing that studies may have underestimated coastal flooding risks. The Washington Post reported that the Department of Interior, which houses the USGS, angered some of the authors by removing this line from the news release on the study: “Global climate change drives sea-level rise, increasing the frequency of coastal flooding.” According to co-author Chip Fletcher of the University of Hawaii, the deletion didn’t make the release wrong—but it did make it incomplete. “It did not cause any direct inaccuracy,” said Fletcher, “but it did eliminate an important connection to be made by the reader—that global warming is causing sea-level rise.”
The Paris Agreement, which aims to hold the global average temperature increase to “well below” 2 degrees Celsius above pre-industrial levels and to pursue efforts to limit that increase to 1.5 degrees Celsius, enters into force Friday. Just three days later, the Twenty-Second Conference of the Parties to the United Nations Framework Convention on Climate Change (COP22), kicks off in Marrakech, Morocco. But, discussion of fundamental issues of the Paris Agreement’s implementation such as transparency rules, climate finance or pre-2020 carbon cuts may be overshadowed—at least in the first few days—by the results of the Nov. 8 U.S. presidential election reports Climate Home.
When it comes to implementing the Paris Agreement, there’s a lot of negotiating left.
“Whilst Paris’ entry into force is great news it’s a bit of a shock for negotiators who weren’t expecting it for a few years yet,” said Camilla Born, a policy advisor at E3G. “Decisions on how the sequencing will work now that particular landmark has been brought forward will be made and negotiators will begin work on the rulebook in earnest. The rulebook will be crucial to ensure that countries are able to consistently track progress and create the best foundation for securing upward ambition moving forward.”
So what exactly is left to decide? For one, financing. There’s still uncertainty surrounding the pathway to mobilizing $100 billion in climate finance for developing countries by 2020, the rules for reporting finance, and how to scale up adaptation finance.
A new report published by the Harvard Belfer Center features a collection of expert briefs—two penned by colleagues at the Nicholas Institute for Environmental Policy Solutions—that addresses the opportunities for, and challenges to, elaborating, implementing, and complementing the Paris Agreement.
Study Highlights Significance of Limiting Warming for Mediterranean
According to a study published in the journal Science, southern Spain and other parts of the Mediterranean region could become a desert by 2100 absent efforts to sharply limit global average warming.
The authors reached that conclusion on the basis of historical vegetation data and computer models, which they used to forecast the likely impact of climate change on the region under four greenhouse gas emissions scenarios, including two scenarios reflecting the two ends of the Paris Agreement’s global warming limit range—1.5 degrees Celsius to 2 degrees Celsius above pre-industrial levels. They found that the region would avoid desertification only if global warming remains at or below 1.5 degrees Celsius this century. Average global temperatures have already risen by 1 degree Celsius since pre-industrial times.
“With 2 degrees of warming, for the Mediterranean we will have a change in the vegetation which has never been known in the past 10,000 years,” said lead author Joel Guiot of Aix-Marseille University.
“The main message is really to maintain at less than 1.5C,” he added. “For that, we need to decrease the emissions of greenhouse gases very quickly, and start the decreasing now, and not by 2020, and to arrive at zero emissions by 2050 and not by the end of the century.”
Sea Level Rise May be Underestimated
The longest and highest-quality records of historical ocean water levels may have underestimated the amount of global average sea level rise that occurred during the 20th century, according to a new study in the journal Geophysical Research Letters.
“It’s not that there’s something wrong with the instruments or the data,” said Phillip Thompson, associate director of the University of Hawaii Sea Level Center in the School of Ocean and Earth Science and Technology, Manoa, “but for a variety of reasons, sea level does not change at the same pace everywhere at the same time. As it turns out, our best historical sea level records tend to be located where 20th century sea level rise was most likely less than the true global average.”
The authors, from the National Aeronautics and Space Administration (NASA) and the University of Hawaii, suggest it is “highly unlikely” global average sea level rose less than 5.5 inches during the 20th century—most likely rise was closer to 6.7 inches.
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.
A new study in the journal Scientific Reports suggests that the evidence to pinpoint expected acceleration of sea-level rise due to climate change was hiding behind the effects of a 1991 eruption of Mount Pinatubo. This eruption sent tens of millions of tons of sulphur dioxide into the stratosphere and may have masked the effects of industrial pollution on global sea levels during the two decades since.
“What we’ve shown is that sea level acceleration is real, and it continues to be going on, it’s ongoing, and we understand why you don’t see it in the short satellite record,” said John Fasullo, who conducted the research along with scientists from the University of Colorado in Boulder and Old Dominion University. The data from satellite observations that scientists have used to track sea-level rise began in 1993, two years after the eruption, which temporarily cooled the planet. These data indicated that the rate of sea-level rise was holding fairly steady at about 3 millimeters per year.
“When we used climate model runs designed to remove the effect of the Pinatubo eruption, we saw the rate of sea level rise accelerating in our simulations,” Fasullo said. “Now that the impacts of Pinatubo have faded, this acceleration should become evident in the satellite measurements in the coming decade, barring another major volcanic eruption.”
Climate Change Extending Mosquito Season, Raising Zika Risk
A portion of last week’s opening Olympic ceremonies in Rio de Janeiro focused squarely on climate change. A video offered a glimpse of climate change effects and an accompanying graphic showing the incursion of sea-level rise on cities around the world if the average global temperature were to increase 3–4 degrees. Fitting perhaps, suggested The Washington Post, given warming could help accelerate outbreaks of mosquito-borne illnesses such as Zika, which has spread from Brazil to Florida, leading to serious birth defects.
Although data confirming a formal link between climate change and the rise and spread of the virus are lacking, Climate Central reports that the initial Brazilian outbreak of Zika was “aided by a drought driven by El Niño, and by higher temperatures caused by longer-term weather cycles and by rising levels of greenhouse gas pollution.” Climate Central’s own research recently showed that in three quarters of major U.S. cities warming temperatures have lengthened the mosquito season—the number of days hot and humid enough for mosquitoes to be biting. According to that research, the ten cities with the biggest increase in the length of the mosquito season over the last 30 years were Baltimore, Maryland; Durham, North Carolina; Minneapolis, Minnesota; Myrtle Beach, South Carolina; Raleigh, North Carolina; Portland, Maine; St. Louis, Missouri; Pittsburgh, Pennsylvania; Worcester, Massachusetts; and Albany, New York.
For Rio, Zika is not the only health risk potentially increased by longer, rainy summers.
Ratifying the Paris Agreement
In Paris last year, more than 190 countries pledged to hold the global average temperature increase to “well below” 2 degrees Celsius above pre-industrial levels and to pursue efforts to limit that increase to 1.5 degrees Celsius. But keeping within that 1.5 degree Celsius target, The Guardian reports, will be extremely difficult.
An analysis by the Ministry of Foreign Affairs of the Republic of the Marshall Islands—the third country to ratify the Paris Agreement—suggests that the agreement is nearing a critical threshold of pledges and is likely to enter into force this year or in early 2017. The agreement takes effect 30 days after at least 55 countries representing at least 55 percent of the world’s greenhouse gas emissions ratify it. The Marshall Islands analysis indicates 58 countries together representing nearly 54 percent of global emissions have either ratified or pledged to work toward ratification of the Paris Agreement by the end of the year.
So far, 22 nations accounting for 1.08 percent of emissions have formally ratified the deal, according to the United Nations.
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.
Scientists have warned that even a few degrees rise in global temperatures can lead to increasingly severe storms. Now an international team of climate scientists has linked man-made climate change to historic flooding that hit the south of England in the winter of 2013–2014. It’s the first time a peer-reviewed research paper has connected climate change to a specific flooding event.
In an article published in Nature Climate Change, the team said that their climate model simulations showed that anthropogenic warming not only increased the amount of moisture the atmosphere can hold but also caused a small but significant increase in the number of January days with westerly flow, both of which increased extreme precipitation. The authors explained that climate change “amplified” the violent storms that led to the area’s wettest January in more than a century and that it has likely increased the number of properties at risk and raised the costs of a flooding event.
Based on more than 130,000 simulations of what the weather would have been like with and without human influence on the climate, the study finds that man-made greenhouse gas emissions have raised the possibility of extreme flooding by 43 percent.
“What was once a 1 in 100-year event in a world without climate change is now a 1 in 70-year event,” said study co-author Friederike Otto of Oxford University.
The study—which analyzed circulation in the atmosphere, the additional risk of rainfall, and swollen river flows and then calculated flood potential in the Thames River Basin—goes beyond previous attempts to connect climate change with specific weather events, tracing connections “all the way from the changes in the atmosphere to the impacts on the ground,” lead author Nathalie Shaller of Oxford University told Agency France Presse.
“This study highlights the fact that we need a better understanding of not just how and where climate change is warming the atmosphere, but also how it is changing patterns of wind and rain, in order to best prepare for extreme rainfall and floods,” said Ted Shepherd, a climate change expert at the University of Reading.
Long-Term Warming Not Unpredictable
Large sustained changes in global temperatures do not rise or fall erratically long term, suggesting the importance of changes in atmospheric circulation and the transfer of energy in balancing Earth’s temperature after a warming event. That’s according to a study published in the Journal of Climate by researchers at Duke University and the National Oceanic and Atmospheric Administration (NASA).
“The bottom line of the study is that the Earth is able to cool itself down after a natural warming event, like an El Nino,” said lead author Patrick Brown, a Duke Ph.D. student. “So then in order to have sustained warming for decades to centuries, you really do need these external drivers, like the increase in greenhouse gases.”
Using global climate models and NASA satellite observations from the last 15 years, the authors cite the Planck Response—the huge increase in infrared energy Earth emits as it warms—for the planet’s capacity to restore the stability of global temperatures. Other important factors, say the authors, are energy transport from the tropic Pacific to polar and continental locations and a net release of energy across cooler regions during unforced, natural warming events.
Studies: East Coast Should Prepare for Warming-Related Sea-Level Rise
Two studies published this week point to regional differences in climate-change-related sea-level rise, specifically, to greater impacts for the U.S. East Coast. A study in Nature Geoscience by researchers at the National Oceanic and Atmospheric Administration (NOAA) finds that “Atlantic coastal areas may be particularly vulnerable to near-future sea-level rise from present-day high greenhouse gas emission rates.” A second study in Proceedings of the National Academy of Sciences finds a higher-than-expected contribution by thermal expansion to sea-level rise from 2002 through 2014—expansion that led to a rapid rise for the East Coast and a slight temporary drop for the Pacific Coast.
Using a climate change model that simulates the ocean, the atmosphere and carbon cycling, the NOAA study examined sea-level rise in the Atlantic, versus that in the Pacific, under multiple global carbon emissions scenarios. It found that if greenhouse gas emissions rates remained consistent with today’s rates, seal levels in the Atlantic would rise much faster than in the Pacific. The difference owes to the Atlantic’s greater “overturning” ocean circulation that connects waters off New York with those off Antarctica. If this circulation slows due to climate change, the researchers concluded that less cold water will dive to ocean depths, warmer water will pool below the surface, and overall warmth will increase. This warm water expands, causing the study’s expected sea level rise, which will have regional variations based on topography and other factors.
The study in the Proceedings of the National Academy of Sciences put the contribution of thermal expansion to rising sea levels at 50 percent. Based largely on satellite readings of changes in water volumes and masses in seas, the study suggests that tallies of the effects of ocean warming on sea-level rise using autonomous seafaring instruments have underestimated thermal expansion.
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.