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Fast and Getting Faster: The Verdict on Sea Level Rise from the Latest National Climate Assessment

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Sea level rose more rapidly during the 20th century than during any of the previous 27 centuries, and humans bear the lion’s share of the responsibility for that rise. That’s just one of the sobering takeaways from the U.S. Global Change Research Program’s Climate Science Special Report (CSSR), released today, but leaked to the New York Times in August. Billed as Volume 1 of the Fourth National Climate Assessment (NCA), the CSSR captures the state of sea level rise science and its implications for the coasts of our country.

Here are six noteworthy findings from the sea level rise section of the CSSR:

1. People are responsible for 80% of the sea level rise since 1970

The first key finding in the CSSR’s sea level rise chapter contains a bold statement that is backed up in the chapter’s main text: “Human-caused climate change has made a substantial contribution to [global mean sea level rise] since 1900…contributing to a rate of rise that is greater than during any preceding century in at least 2,800 years…”

This finding is based on eight independent studies published in the last three years that aim to quantify the human contribution to sea level rise since 1900. All of them conclude that the human contribution is “substantial,” and at least two find that, in the absence of human activity, sea level rise over the course of the 20th century would have been about 50 to 60% of what has actually been observed.

The human contribution to sea level rise is even more striking if we look at just the last 50 years: People are responsible for about 80% of the global mean sea level rise since 1970.

These findings broadly reflect the rapid evolution of attribution science–or assessing whether–or what proportion of–observed climate and weather events can be attributed to human activity. A recent study published by Brenda Ekwurzel and others takes this sea level rise attribution one step further by showing that about 30% of global sea level rise since the Industrial Revolution was caused by the burning of products from 90 major fossil fuel companies.

Given the tendency of climate-confused politicians such as Scott Pruitt to say things like “Science tells us that the climate is changing and human activity in some manner impacts that change…the human ability to measure with precision the extent of that impact is subject to continuing debate and dialogue, as well they should be,” this high-confidence finding would ideally help to lift some of their “confusion.”

2. Sea level rise is accelerating, and a growing proportion of that rise is due to loss of ice on land

Estimates of how much sea level rose over the course of the 20th century have been changing, which has implications for our understanding of how the pace of sea level rise has been changing. The average rate that has long been quoted for the 20th century, from a 2011 study by Church and White, is 0.06 inches/year. But a few more recent studies, including one by Hay et al. cited in the CSSR, have found that rate to be slightly lower–0.05 inches per year. That amounts to 4-5 inches of sea level rise in the 89 years between 1901 and 1990.

Since 1990, less than 30 years ago, global sea level has risen by about 3 inches. The rate of sea level rise is now 0.13 inches per year–more than double the 20th century average–with both tide gauges and satellite data confirming the changing pace.Over the course of the 20th century, the pace of sea level rise varied. This recent acceleration is different for at least a few reasons. First, it’s coming on the heels of a century of already above-average sea level rise that we know is attributable to human activity. Second, projections show that this acceleration has only just begun. And third, loss of land-based ice is contributing more to sea level rise than it did during the 20th century.

The six scenarios used by the CSSR to project future sea level rise show that the rapid pace of sea level rise we are experiencing today could pale in comparison to what lies ahead. With an intermediate scenario, the pace of sea level rise would increase to 0.2 inches per year in 2020 and to 0.6 inches per year in 2090. With a high sea level rise scenario, those rates increase to 0.4 inches per year in 2020 and 1.7 inches per year in 2090.

The six sea level rise scenarios developed by NOAA as input to the Climate Science Special Report for the National Climate Assessment.

Changes in sea level arise largely from two sources: loss of land-based ice and warming of the ocean, which causes seawater to expand and take up more space. Over the course of the 20th century, warming oceans contributed the bulk of the sea level rise signal. But since 2005, about two-thirds of observed sea level rise has come from loss of ice. When we look into the future, there is still a considerable degree of uncertainty about how much ice loss will contribute to sea level rise.

3. Antarctic ice loss is still a wildcard, but its game-changing potential contribution is becoming clearer

Quantifying the response of the Greenland and Antarctic ice sheets to future warming has been a consistently large source of uncertainty in global sea level rise projections for over 15 years (here’s the third IPCC report from 2001, for example). In the past couple of years, however, major developments in the ability to model the response of the Antarctic ice sheets to warming have begun to hone our understanding of Antarctica’s potential contribution to sea level rise this century.

And it’s scary.

The CSSR is unequivocal that Antarctica (and Greenland) are losing ice, and there is a growing body of evidence suggesting that the pace of that loss is accelerating. The rate of ice loss is about 100 gigatons per year–an amount that this Washington Post article can help us to wrap our heads around.

The Thwaites Glacier, part of the West Antarctic Ice Sheet, appears to be in “an irreversible state of decline,” according to a 2014 study by Eric Rignot and others.

Models suggest that ice loss from Antarctica could contribute more than three feet to global sea level rise this century on top of rise from other sources. This growing body of knowledge is reflected in what the CSSR calls an “extreme” scenario in which sea level rises by an average of 8.5 feet by 2100. The previous NCA report’s highest sea level rise scenario projected about 6.6 ft by 2100.

There’s a concerted effort in the CSSR to incorporate the latest science about Antarctic ice loss into sea level rise projections. But there’s still enough uncertainty that Antarctica’s potential contribution couldn’t be fully accounted for when assigning probabilities to potential sea level rise futures.

4. Sea level rise scenarios tied to emissions scenarios and assigned likelihoods

NOAA has developed a new set of sea level rise projections that are designed for this round of the National Climate Assessment. New SLR scenarios designed for understanding risk given a range of different carbon emissions scenarios. Each sea level rise projection is assigned a probability based on emissions pathways, as in “with a high emissions scenario (RCP8.5), the ‘very likely range’ of SLR is about 1.7-4.3 ft by 2100”.

Here’s where the big Antarctic wildcard plays in, though: The probabilities do not factor in the possibility of major ice loss from Antarctica.

5. Communities will be affected by more frequent, more severe flooding before they are permanently underwater

Since 2014, there’s been an increased focus on what happens between now and the point at which coastal regions are permanently underwater due to sea level rise. This in-between time will be characterized by an increase in the number and extent of high tide flooding events, and a number of studies in the past three years have painted a picture of what that looks like quantitatively and qualitatively.

 

King tide flooding in Charleston, SC, on October 7, 2017. The local National Weather Service office has issued 38 Coastal Flood Advisories for the region already this year.

The CSSR puts this issue of tidal flooding up front in key message #4: “As sea levels have risen, the number of tidal floods each year that cause minor impacts…have increased 5- to 10-fold since the 1960s…Tidal flooding will continue increasing in depth, frequency, and extent this century.”

While the tidal flooding findings described here won’t be news to regular readers of this blog or to residents of flood-prone places like Charleston and Annapolis, their elevation to key finding status will hopefully highlight the insidious threat of frequent flooding that hundreds of communities in the U.S. could face in the coming decades.

6. Buckle up for centuries of sea level rise

When we look at projections for how much sea level will rise through the end of this century, it’s tempting to assume that 2100 is so far off that of course we will have cracked the climate change nut by then and be back to a climate that feels right. A climate in which people will know what a month of below average temperatures feels like. A climate in which coastal towns see a couple of high tide floods per year instead of dozens.

But sea level takes time to respond to the emissions we are pumping into the atmosphere, and even if temperatures stabilize, sea level is projected to continue rising for centuries if not millennia. Emissions through 2100 could lock us into a sea level rise of 12 feet by 2200 and up to 33 ft in the next 2,000 years.

Again, major ice loss from the Antarctic ice sheet is the big wildcard because once that ice is lost, it cannot easily be regained. The CSSR states: “Once changes are realized, they will be effectively irreversible for many millennia, even if humans artificially accelerate the removal of CO2 from the atmosphere (DeConto and Pollard 2016).”

This new report shows us that we are on the comfortable end of the steep sea level rise curve. As this report gains attention in the coming days there will be those who will wave their hands and insist “nothing to see here.” Clearly, there is far more to see here than we want. Thank you to the dozens of authors and researchers who are enabling us to see it coming.

 

Sweet et al. 2017 NASA Simran Paintlia for mycoast.org

On Climate Change, a Major Public Health Conference Stands in Stark Contrast to the Trump Administration

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Our nation’s oldest, largest, and most highly respected public health organization—The American Public Health Association—begins its 2017 conference on November 4. Photo: Courtesy of APHA

The Trump administration may be hell-bent on sidelining any effort to address global climate change—or even have an intelligent conversation about it—but the public health community is having none of it. 

Public health experts know full well that climate change is an existential threat to people’s health, safety, and security. So much so that our nation’s oldest, largest, and most highly respected public health organization—The American Public Health Association—declared 2017 as the Year of Climate Change and Health.

“We’re committed to making sure the nation knows about the effects of climate change on health. If anyone doesn’t think this is a severe problem, they are fooling themselves.”  APHA Executive Director Georges Benjamin, in The Washington Post

The organization is also ready to host its annual meeting. Attended by thousands of public health professionals from around the country, the theme of this year’s meeting is Creating the Healthiest Nation: Climate Changes Health.

I’m struck by the enormous disconnect between what is happening in our nation’s capital and what’s happening in the community of public health experts. There is quite a gulf on so many issues—from gun violence, reproductive health, exposure to pesticides and other toxic chemicals, and worker safety to minimum wage and health disparities.

But let’s cut to the chase and talk about climate change.

Sidelining climate change: A round-up of recent Trump administration actions

We all know where President Trump stands on climate change; we knew it well before he took office. His suggestion that global warming was a hoax perpetrated by the Chinese is maybe his most memorable tweet on the issue, but he’s followed up this nonsense with real action—perhaps best personified in the successful nomination of Scott Pruitt to head the Environmental Protection Agency. And then fulfilling his promise to withdraw from the Paris Climate Agreement. Followed by fossil-friendly Pruitt announcing his intention to repeal the Clean Power Plan.

And they are just getting started, using every tool in the toolbox.

Here is a quick round-up of the administration’s efforts to seriously sideline climate change – just over the past couple of weeks.

Keeping climate change front and center: A look at the APHA public health conference

Public health scientists and practitioners have been raising the alarm about climate change and its impacts on human health for years (see for example, here, here, here, here, and here). And just this week, the Lancet, a prestigious medical journal, released a report on climate change and health, noting that its  impacts are “far worse than previously understood.”

This year’s APHA annual meeting stands in stark contrast to the control, alt, delete strategy we see coming out of Washington. I’ve done a quick scan of the upcoming APHA program and its keynote addresses, panel presentations, scientific sessions, posters, group gatherings, and continuing education offerings that are in store for the thousands of public health professionals and advocates who will be attending next week’s meeting.

Here’s just a snapshot of the breadth and depth of the discussions that will be happening.

  • Opening Plenary Session: Climate Changes Health
  • President’s Session: Climate Change and Health: The 21st Century Challenge
  • Global Faith and Health Perspectives on Climate Change: An Interfaith Celebration
  • Climate Change and its Impact on African Americans (Poster)
  • Climate Change and Vulnerable Populations
  • Nature and Human Health: Vectors and Climate Change
  • Climate Change and the Medical Care System
  • Climate Change and Disaster Preparedness
  • Climate Change Denial: Who Will Suffer Most and First?
  • Climate Change and the Possible Effects on Arbovirus Transmission in the Americas
  • Reproductive Health and Carbon Footprints
  • Climate Change and Health in Epidemiological Research
  • Climate Change, Energy, and Heat: Implications for Human Health
  • Climate-friendly Farming: A Public Health Imperative
  • Climate Change and Children’s Health
  • Ethics, Environmental Justice, and Climate Change
  • Climate and Geospatial Determinants of Health
  • Best Practices of Policy Initiatives at the Local and Community Level to Address Climate Change

On Sunday, I’m heading to Atlanta to attend the annual meeting. It’s something I look forward to every year. It’s an opportunity to reconnect with colleagues from across the country; hear about new findings, issues, and initiatives from public health researchers and practitioners; share and test ideas; peruse new books, products, and educational resources in the popular exhibit hall (while picking up a couple of free tchotchkies and an occasional apple or piece of candy); and then come home with renewed energy and new friends.

APHA is a vibrant, active, and diverse community and, for me, the meeting helps recharge my battery. It’s like an annual booster shot. And this year’s booster is all about climate change.

Trust and listen to the public health community, not the Trump administration

There is real leadership here—and it’s not coming out of Washington.

The public health community, with far less capacity and significantly fewer resources than our federal government, is WAAAY ahead when it comes to understanding, exploring, planning, managing, advising, educating, and otherwise addressing climate change.

We can count on this community (my community) to put public health, public safeguards, and public protections first—including those focused on climate change. These experts come from every state in the nation and can bring voices and expertise to bear at every level of government.

We will come out of Atlanta next week more prepared and committed than ever to speak up, speak out, and hold our leaders accountable for failing to address this existential threat.

APHA members and public health supporters participate in the March for Science on April 22. Photo: David Fouse/APHA

Pruitt Seeks to Reopen Truck Pollution Loophole per Cronies’ Request

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That shiny new truck could have a 15-year-old engine that doesn’t meet today’s standards, and you may never know…except for the plumes of pollution behind it, if it’s a glider vehicle. Photo: Jeremy Rempel. CC-BY-ND 2.0 (Flickr)

In a particularly scary development, the EPA just proposed to repeal part of the recent regulations on heavy-duty vehicles. The proposal would affect “glider vehicles” and would reopen a loophole so big you could, well, drive a truck through it…leaving a ridiculously large cloud of pollution in its wake.

What the heck is a glider?

Glider vehicles are trucks that are built from a refurbished engine and a brand-new chassis (called a “glider kit”).  They have been around for a long time and can serve a useful purpose—heavy-duty diesel engines are built to last hundreds of thousands of miles and are a significant part of the upfront cost of a vehicle, so if you crash your truck in the first couple years, it would be worth it to make sure you got the full lifetime use out of that powertrain.

The thing is, no one’s going joyriding in a semi—truck drivers are doing it for a living and generally try to take immaculate care of their vehicle, so one wouldn’t think these types of accidents are very frequent.  In fact, up until recently, only a few hundred such gliders were sold in a given year.

Glider sales on the rise…

That all changed in the past couple years, when members of the glider cottage industry decided to exploit a loophole.  In 2007 and 2010, EPA put into effect new pollution controls for heavy-duty vehicles which cut soot and smog-forming nitrogen oxide emissions by more than 90 percent.  However, because there is a menagerie of truck types and uses, those regulations are based on emissions tests of the engine, not the vehicle.

Fitzgerald, the leading assembler of glider vehicles, decided to make a few bucks by building a brand around assembling new glider vehicles with old, polluting engines that predate the EPA’s regulations and then selling the trucks as new vehicles.  They and other glider assemblers even put out ads trying to increase the availability of these more polluting engines!

Glider vehicle assemblers typically offer the trucks at a significant discount compared to other new vehicles—it’s amazing at how much cheaper you can make a truck when you don’t care about how much pollution it’s spewing (about 25 percent cheaper, in fact).  This is one of the major complaints from the rest of the industry—it isn’t a level playing field.  In fact, most of the industry is opposed to glider vehicles.

…leads to a LOT of excess pollution

Of course, the public shouldn’t be too crazy about these trucks, either.  Thanks to that “pollution discount” for not meeting modern emissions standards, glider vehicle sales have gone through the roof—just a few hundred glider vehicles were sold a decade ago, but industry sales are now up to about 10,000 vehicles…and perhaps still on the rise.

So just how bad is it?  Virtually all of Fitzgerald’s vehicles are sold with a pre-2004 diesel engine.  Those engines emit upwards of 10 to 20 times the amount of soot and smog forming nitrogen oxides (NOx) of a brand-new engine.  By 2025, EPA’s own analysis shows that these gliders would be emitting about 300,000 tons of NOx and 8,000 tons of soot each year!

Putting that into perspective:

  • That amount of NOx is about 10 times that of the VW Dieselgate scandal (to date)…all in a single year!
  • These levels of NOx emissions would effectively cancel out the reductions in NOx made in passing EPA’s Tier 3 Emissions and Fuel Standards.
  • Small in numbers but not impact—despite representing just 5 percent of the long-haul trucks on the road, by 2025 these glider vehicles would emit about 1/3 of all soot and NOx pollution from long-haul trucks.
  • These excess emissions would have serious health impacts—if this loophole isn’t closed by 2025, these glider vehicles would result in up to 12,800 deaths that could have been prevented, not to mention countless additional emergency room visits and other health issues.

It’s also worth noting that the engines being put into these new trucks are engines that EPA had already previously found in non-compliance with the Clean Air Act because of the use of defeat devices.  That’s right–not only do these engines not meet today’s emissions standards, but they didn’t even meet the emissions standards in place when they were originally manufactured!

In the most recent heavy-duty vehicle standards, the EPA wisely closed this loophole by requiring all new vehicles, including gliders, to have an engine that meets the same model-year standard as the vehicle itself.  Recognizing the previous legitimate use of gliders, they even allowed a small-volume exemption for up to 300 vehicles, curbing the rampant exploitation of the loophole while still maintaining a volume that could keep companies like Fitzgerald in business.

Pruitt’s cronyism threatens public health

The EPA Administrator Scott Pruitt is threatening to throw that all away by repealing the sections of the rule that closed the glider loophole.  And he is doing so at the behest of Fitzgerald and Representative Diane Black (R-TN), who’s currently a candidate for the governor of Tennessee.

Rep. Black has tried unsuccessfully to restrict EPA from regulating glider kits via legislative action, willing to sacrifice public health because a few hundred jobs at Fitzgerald are in her district.

Fitzgerald’s owners met directly with Scott Pruitt in May.  They also worked with Rep. Black and a couple smaller glider assembler to submit a petition with some seriously shoddy “evidence” collected by a third party, Tennessee Tech University.  The thing is, TTU’s facilities are…in the Fitzgerald Industrial Park, paid for by Fitzgerald.  Coincidentally I’m sure, these tests were taken and signed off by the head of the center paid for in part by Fitzgerald even before the public-private partnership between TTU and Fitzgerald was announced.

Lo and behold, after receiving the petition from Fitzgerald, Scott Pruitt announced that he would be re-examining the glider provisions of the heavy-duty regulations.

It isn’t clear who exactly benefits from all this backroom dealing (besides the small number of glider assemblers like Fitzgerald)—but it certainly isn’t the American public.

Pending internal review by the executive branch, this proposed repeal should be made available for public comment, so stay tuned as we continue to push back on Scott Pruitt’s ridiculous dismantling of public health protections—I’m sure UCS will be calling on you for your support.

What is the National Climate Assessment? The Most Comprehensive Report on Climate Change in the United States

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The amount of scientific research and brainpower that goes into the National Climate Assessment is kind of astonishing. Scratch that. It’s really astonishing.

This report is on my mind because the first draft of the next version (the fourth National Climate Assessment, or, NCA4) and one of its associated technical reports (the State of the Carbon Cycle) are due to be released for public comment this fall. In addition, the final version of the Climate Science Special Report – billed as Volume 1 of the National Climate Assessment – is due to be released in November.

So far, these reports have proceeded according to plan and are slotted to provide the President, Congress, and the public with the best available science on climate change and its impacts on the United States.

The National Climate Assessment is mandated by Congress

Before I get back to how astonishingly comprehensive the National Climate Assessment is, the National Climate Assessment (NCA) is a report that an office in the White House called the U.S. Global Change Research Program (USGCRP) is required to prepare for the President and Congress every four years. In 1990, President George H.W. Bush signed the Global Change Research Act, which mandates that this report analyze human and naturally caused global changes, and analyze their effects on things like agriculture, energy production, and human health. This Act passed unanimously in the Senate.

The Climate Science Special Report – part of the NCA process – tells you how and why the Earth is changing

The Climate Science Special Report is like going to a doctor and being given a report of your vital signs. It has information on changes in things like the Earth’s temperature, extreme weather events, and sea level, as well as what is causing these changes. The NCA is like being told by a doctor what the symptoms of these changes in your vital signs are going to be like for your community and state (e.g. more sea level rise = chronic flooding along coasts).

The Climate Science Special Report and the NCA consolidate massive amounts of scientific research

Okay, back to the astonishing amount of science that is in the NCA. Take the Climate Science Special Report. Again, this is just one part of the NCA process. In the leaked draft of the Climate Science Special Report (the final version is due to be properly released to the public in November), the authors assess more than 1500 scientific studies and reports. 1500!

I can tell you first hand that publishing a single study in a credible journal is a major feat. First, there’s the time you spend conducting the research (this is oftentimes a multi-year process during which you get feedback from colleagues at conferences). When you have significant results, you write a paper about them. It is standard practice to solicit feedback on your paper from colleagues who have related expertise before you try and get it published. Then, you submit your paper to a journal, which sends your paper to experts in your field who judge whether it is a solid piece of work or not, and offer feedback on the ways that your study and paper can be improved. If your paper is accepted, you have to revise your work according to the feedback received. Then and only then does your paper see the light of day.

Multiply that process by 1500 and you can now get a sense for how much scientific research and knowledge the Climate Science Special Report is based on. Factor in all of the other components of the NCA process that rely on similar amounts of information (e.g. the aforementioned State of the Carbon Cycle Report and the full NCA itself), and you now have a sense for how astonishingly comprehensive the NCA is.

The NCA tells us what the state of the science is on climate change and its impacts for the United States

The experts involved in the NCA and its associated technical reports not only review massive volumes of scientific studies, they spend large amounts of time comparing their findings.

For any given topic, the experts systematically look at what studies found and how similar the results are, as well as how many studies have been carried out on the topic. The experts then use all of that information to carefully communicate exactly what science can tell us on any given topic. The findings in the NCA are thus not radical, but reflect careful assessments of large volumes of science. As a result, Americans have a place that they can rely on to learn what the state of the science is on climate change and its impacts.

The NCA is authored by hundreds of experts from across the country

In addition to the sheer volume of information contained in the Climate Science Special Report and the full NCA, the reports are also incredibly rigorous with respect to the number and breadth of experts involved and the amount of scrutiny the reports undergo.

More than 300 experts were involved in the third version of the NCA. 50 authors contributed to the forthcoming Climate Science Special Report.

The Climate Science Special Report, State of the Carbon Cycle, and the full NCA itself undergo extensive review and offer a platform for feedback from diverse perspectives. The full process is outlined here, but in a nutshell, the reports are open for review by technical experts from both within and outside of the government, the National Academy of Sciences, and the public alike. The previous NCA received 4161 unique comments in total. Report authors are required to respond to each comment submitted.

The NCA provides critical information on risks from climate change for decision makers

The NCA provides critical information on the impacts of climate change on well-being and the economy of the United States. However, it stops shorts of making policy recommendations – it leaves it up to decision-makers to decide what to do about the risks that the report identifies.

Because the NCA and associated technical reports are so comprehensive and rigorous, they offer an unparalleled starting point for decision-makers, our military, the private sector (the report is broken out by sector), and members of the public alike to both assess the risks that Americans are facing and consider solutions so that we can chart a prosperous and secure path forward.

 

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