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Denying the Storm: Climate Change Report Findings the Trump Administration Doesn’t Want You to Know About

Yesterday, the New York Times published the final draft of a broad-based U.S. climate change report. And given the fact that the Trump Administration, brimming with politically-contrived climate change denial, is still pushing full steam toward a reckless withdraw from the Paris Climate Summit, we’re pretty confident that it’s hot information they don’t want you to get your hands on.

The report carries with it a monumental scientific gravitas. A level of credibility that Trump, even in his wildest fantasies, couldn’t hope to achieve. It includes a culmination of research coming from thousands of peer-reviewed studies resulting in the accumulated work of tens of thousands of scientists. The National Oceanic and Atmospheric Administration (NOAA) served as the lead government agency conducting the report. Representatives from three other federal agencies joined with NOAA along with a team of 54 scientist authors and reviewers drawing from both public and private sector institutional knowledge in compiling the report.

The 673 page report represents a massive body of the latest scientific findings on climate change. It includes numerous key advances in understanding which we will take a shot at briefly highlighting for you here.

Humans Are the Primary Cause of Warming by a Huge Margin

The key finding of the report is that humans are causing the Earth to warm very rapidly. The study noted a 95 to 100 percent likelihood that human activity produced the approximate 0.85 C warming since the mid 20th Century and the 0.7 C warming since 1986. For the U.S., the report finds that recent decades have been warmer than any time within the last 1500 years. Meanwhile, it forecasts that future decades will at least be the warmest experienced in tens of thousands to millions of years.

(Tens of thousands of climate scientists agree — the considerable warming trend we’ve seen since the 1880s has been caused by human emissions. Image source: Climate Report.)

The report goes on to state that there is no convincing line of scientific evidence that provides a cause for this warming other than human emissions. That the increasingly accurate observations of solar and volcanic activity reveal only very minor nudges to the climate system compared to the vast heat-trapping influence of human-emitted greenhouse gasses. Meanwhile, though natural variability influences like El Nino and La Nina have effects on climate over months and years, the global impact of these natural sources greatly diminish over the course of the decades long warming regime that is now well established.

Future Warming is Locked in, But it Can be Dramatically Reduced by Cutting Carbon Emissions

Overall, the future isn’t looking too good. Because of past and current human emissions (coal, oil, and gas burning), the report finds that global climate change is projected to continue throughout this Century and beyond. Rapid cuts to greenhouse gas emissions, according to the study, were needed to have a chance of limiting warming to 2 C this Century. But the study found that even an immediate stabilization at present levels of atmospheric greenhouse gasses by ceasing present emissions would result in 0.6 C additional warming compared to recent decades. Longer term, the study points to a necessity that atmospheric CO2, methane, and other greenhouse gasses fall below present levels to meet the goals of preventing 2 C warming over the long term.

Continued emissions result in considerably more warming, according to the study, with temperatures hitting as high as 5 C or more above 1901 to 1960 averages if policies like Trump’s result in renewed increases in fossil fuel burning. What this means is that we can considerably limit the amount of damage caused by human-forced climate change if we rapidly cut emissions in the near term. But if we fail to do that, and Trump is leading us down this more dangerous path by killing the Clean Power Plan and backing out of the Paris Climate Summit, then temperatures will rise into extraordinarily hot and harmful ranges.

The study finds with high confidence that we presently remain on the higher emissions scenario pathways excepting a pause in emissions increases during 2014 and 2015. The study also finds that present rates of greenhouse gas emissions reductions are not yet in line with the goals of the Paris Climate Accord.

Extreme Weather is Becoming More Common and More Attributable to Human Caused Climate Change

Perhaps the most important new takeaway from the report is a developing clearer view of the impact of present warming on severe weather events. The report finds that many temperature and precipitation extremes are becoming more common. That the number of high temperature records over the past twenty years greatly exceeds the number of low temperature records. And that heavy precipitation events have increased in both frequency and intensity. Much evidence has been found for a human-caused influence on soil moisture deficits due to evaporation that leads to more rapid drought intensification. And the incidence of large fires in the Western United States has increased significantly since the 1980s and is expected to increase further.

The study also finds that Northern Hemisphere snow cover and water held in snow has declined. That there has been a decrease in snowstorm frequency along the southern margins of snowy areas. That the Arctic is losing more than 3.5 percent of its sea ice coverage every decade and that September sea ice extent is declining by more than 10 percent per decade. That Arctic land ice losses are also accelerating. It notes a contested scientific linkage between the increased severity of winter storms and a rapid observed warming in the Arctic. The study also identifies changes in tornado frequency and notes a possible linkage between thunderstorm wind intensity, increased convection, hail and climate change. Moreover, the study finds a global intensification of thunderstorms overall as the world has warmed. Tropical cyclone peak intensity is expected to ramp up even as typical cyclone formation regimes are altered.

Perhaps more disturbing is the fact that the study identifies an emerging understanding that human-caused climate change is starting to affect larger natural variability based systems like El Nino, the North Atlantic Oscillation, the North Pacific Oscillation, the Pacific North American Pattern, the Jet Stream, the size of the Tropics, atmospheric circulation patterns, rivers of moisture and storm tracks to varying degrees and with varying degrees of certainty or uncertainty. These systems not only play a major role in present global weather patterns, but our understanding of how they operate is also critical to our ability to predict weather. So climate change based alterations in these larger systems creates higher levels of uncertainty with regards to extreme weather risks.

The key takeaway of all this being that:

Some extremes have already become more frequent, intense, or of longer duration, and many extremes are expected to increase or worsen, presenting substantial challenges for built, agricultural, and natural systems.

Harmful Impacts to Oceans are on the Rise

Oceans, another key aspect of the health of the Earth’s life support system, according to the study, are warming, rising, becoming more acidic, and risk becoming stratified as they lose oxygen.

The study found that the oceans have absorbed 93 percent of the excess heat produced by human greenhouse gas emissions. That this added heat is having a number of serious effects. For one, the rate of sea level rise was found to be faster than at any time in the past 2,800 years. That end Century projections for sea level rise are heavily dependent on future emissions and range from 1 to 8 feet in the study.

The study finds that even present rates of sea level rise have resulted in significant increases in the incidence of coastal flooding. That tidal flooding events has multiplied by 5-10 times the rate observed in the 1960s overall and that the vulnerable Atlantic and Gulf coasts have seen an increase in tidal flooding that is now 25 times times 1960s values due to warming-related sea level rise. As sea level rise accelerates this Century, flooding is expected to considerably worsen — with the most damaging effects happening alongside the highest levels of possible future greenhouse gas emissions. The study also identified potentially compounding effects from possibly worsening Atlantic storms and heavier coastal rainfall events.

Ocean warming and increasing glacial outflows also have a potential to effect ocean overturning circulation in the upper middle latitudes. Of particular interest is the possible disruption of the Atlantic Meridional Overturning Circulation (AMOC) this Century. Recent unconfirmed scientific observation has already pointed to some impacts to AMOC due to warming during recent years. But the report notes that it is presently difficult to validate these observations. Disruption to AMOC would have a considerable impact on North Atlantic weather patterns. It would also reduce both ocean carbon and heat uptake due to a more stratified and less well mixed ocean system. The study identifies a weakening of AMOC of between 12 and 54 percent under worst-case greenhouse gas emissions scenarios.

As risks of ocean stratification mount, acidification of the world’s waters is rapidly increasing. Atmospheric carbon dioxide rising above 400 parts per million was found to worsen detrimental effects by increasing ocean acidity levels. The study found that the rate of ocean acidification increase was unparalleled in the past 66 million years at least. That higher rates of fossil fuel burning and greenhouse gas emissions would result in another doubling or more of ocean acidity by the end of this Century.

Heating, stratifying, and more acidic oceans are also steadily losing oxygen. The study finds that the amount of oxygen held in the oceans is falling coincident with warming. The study identifies a declining ocean oxygen content at intermediate depths and major losses in oxygen in inland seas, estuaries, along coasts, and in parts of the open ocean. Lower oxygen means more ocean dead zones and more toxic anaerobic microbial blooms. Overall ocean oxygen content is expected to fall by 3.5 percent under worst case warming and fossil fuel emissions scenarios by 2100.

Serious Risk of Unanticipated Changes

The level of evidence provided by the study that humans are changing the climate and that these changes are increasingly harmful is mountainous. And this base fact alone is reason enough for a climate change denying Trump Administration to try and bury its findings. But it is perhaps the study’s own admitted uncertainty over future risks that reveals how reckless Trump’s combined denial of climate change and doubling down on fossil fuel based emissions has ultimately become.

The study itself is based on physical model and consensus science findings. This lends weight to the evidence it has provided in that it is highly qualified. However, the study responsibly indicates the potential weak points of model based consensus studies. Models are notably less able to duplicate higher paleoclimate levels of warming — indicating an increased likelihood that rates of warming will be more intense than expected and a reduced likelihood that warming will be less intense than expected. The study also cautions that there is another limitation to the ultimate accuracy of model predictions in that models themselves are unable to capture what it calls critical threshold and compound events.

Compound events are described as multiple extreme climate change events occurring at the same time to generate an unanticipated level of harmful disruption. A good example of a compound event is extreme heat risking injury or loss of life, extreme drought harming crops and water supplies in the same region, and both coinciding with a severe or unprecedented wildfire outbreak. Critical threshold events occur when the climate system crosses a tipping point and then radically adjusts to a new climate state. A worrisome critical threshold event is crossing a tipping point in which significant carbon feedbacks from the Earth System occur — locking in more extreme warming and generating periods in which global temperatures more rapidly spike. Both of these kinds of events have the potential to produce consequences that are difficult or impossible to manage. And the chance of such catastrophic events occurring increases along with higher rates of fossil fuel burning and coinciding higher levels of warming.

The precautionary principle alone demands that we do our best to avoid increasing these uncertain risks even as we steer away from the much more certain harms like sea level rise and generally increasing extreme weather. The science has again given us a more clear, more refined, gift in the form of this very valuable provision of foresight. And yet the current U.S. executive leadership is bound and determined to obstinately ignore or it, cast doubt on it, and do everything possible to cloud the clear and priceless message being sent to us by an army of selfless and dedicated climate researchers.

Links:

Scientists Fear Trump Will Dismiss Blunt Climate Report

Climate Science Special Report

Images taken directly from the report

Hat tip to Greg

Hat tip to Wili

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40 Comments

  1. Given Mr. Trump’s latest ravings, he might be counting on a nuclear winter to deal with the problem of Global Warming.

    Not that that would actually ‘work’.

    The Money behind the politics won’t start to care about these reports until it starts to cost more money than they can make. 😦

    Reply
  2. Keith Antonysen

     /  August 8, 2017

    Thanks Robert.

    Yesterday I came across a BBC article suggesting that Italy’s records of greenhouse emissions are being understated by a large margin, and the same is true for Australia.

    http://www.bbc.com/news/science-environment-40669449#

    In Australia, we had been told that we were exceeding closing down emissions promised at Paris by the previous Environment Minister Hunt. The governments own records say otherwise:

    http://www.smh.com.au/environment/foi-documents-confirm-government-holding-almost-one-years-worth-of-pollution-data-20170706-gx5um3.html

    I wonder how many other countries also have greenhouse gases being voided above official estimates?
    We also have methane escaping from old fracking sites, from cattle, leaking domestic gas lines, and methane voided from tundra areas and bogs.

    Reply
    • The above study listed moderate confidence that emissions had plateaued during 2014 and 2015. The big issue is China’s reporting. If they’re in the correct range, then I think the plateau is probably valid. Although cheating on emissions reporting by countries like Australia and Italy does not inspire confidence.

      Global methane rates of atmospheric increase have thankfully slowed down a bit in recent years in any case. 2014 rates of 12.6 ppb per year were not duplicated during 2015 and 2016 (9.8 ppb and 7.7 ppb respectively). The most rapid rates of annual increase occurred during the 80s and early 90s at 14.4 ppb during 1991. Unfortunately the rates of CO2 increase were near 3 ppm during 2015 and 2016, which should be a somewhat greater concern b/c they were records. However, warmer ocean surfaces associated with El Nino and positive PDO probably provides a periodic bump for those numbers. 2017 should back down a bit. If it doesn’t …

      Reply
  3. Allan Barr

     /  August 8, 2017

    This was a post I did in my climate change survival group on facebook Robert. Your thoughts regarding the findings by Natalia Shakhova et al would be appreciated. They are methodically nailing down their thesis for abrupt emissions of CH4 from the arctic.

    This paper may be a little much for some, in short it explains the mechanisms for abrupt destabilization of methane clathrates and subsequent emissions of significant amounts of CH4. Natalia et al are nailing down their hypothesis of a probable 50 billion ton burp which could occur at any time.
    50 billion tons implies an abrupt increase in global temps of at least 1.3 C, possibly more. When one remembers that these estimate are all conservative it really makes me question the sanity of continued emissions of CO2 by our civilization.
    According to Dr. Shakova: “As we showed in our articles, in the ESAS (East Siberian Arctic Shelf), in some places, subsea permafrost is reaching the thaw point. In other areas it could have reached this point already. And what can happen then? The most important consequence could be in terms of growing methane emissions… a linear trend becomes exponential. This edge between it being linear and becoming exponential is very fine and lies between frozen and thawed states of subsea permafrost. This is what we call the turning point…. Following the logic of our investigation and all the evidence that we accumulated so far, it makes me think that we are very near this point. And in this particular point, each year matters. This is the big difference between being on the linear trend where hundreds and thousands of years matter, and being on the exponential where each year matters.”

    https://www.nature.com/articles/ncomms15872

    Reply
    • I think it’s very unlikely given present warming levels at 1.2 C. More of a risk in the 2 to 4 C range considering when those carbon stores were laid down. But that said an immediate release of a store that size would tend to be a lower risk I think. Maybe on the century timescale.

      Reply
      • Allan Barr

         /  August 9, 2017

        Lets say, what if these observational scientists with decades of knowledge are correct? Would love to see you spell it out in a post.

        Reply
        • We’ve got a couple of scientists who are cutting hard against the mainstream of scientific thought. We’ve got no indication at this time that ESAS is ramping up to this kind of big blow in the larger methane monitors. I’m not going to completely discount S&S. But in order for me to move forward with an additional analysis, they need to provide more than just these speculative dots thrown out on the map. Sure, we have an apparent surge in methane coming from this region of one or two orders of magnitude — from practically nothing to maybe 20 million tons per year soon. But 20 million tons per year is 2500 times less than 50 billion tons in one year. We have no evidence that a similar methane burp happened during the Eemian when temperatures were about the same as they are today. I need more proof than the present reports provide before I go off that speculative deep end. I’m not going to ignore that pair of nutty scientists on the proverbial volcano. But I need more confirmational evidence going forward. If we had a big jump to 100 million tons per year from the same region that does result in a higher rate of atmospheric methane accumulation and that atomic analysis confirms was sourced from these stores, then that would be something. But as long as these rates of release hold about steady or slowly grow, we can just chalk it up to generally higher pressure on the store and generally larger feedback without looking at potential doomsday scenarios and going off half cocked. In addition, I’m very wary of Russia-based sensational misinformation at this time. These scientists may or may not be caught up in that. But I can’t keep my eye off that ball either.

          My personal opinion, based on a broader reading of the science and looking at the larger methane monitor data, is that identifying this risk at 1.3 C warming is both premature and looks somewhat contrived. We have had 1.3 C warming or more at around 120,000 years ago without a 50 billion ton methane blow out. As I said before, I’d be more concerned about the 2 to 4 C range. But I don’t think this whole 50 billion tons in one year thing is inevitable by any stretch. I’d like to see some other scientists look at this system and see what they come up with. But there’s basically not much new to go with here at this time for me.

          In any case, volcanoes make a good deal of noise as they set up for a big blow. I suspect that a big methane burp would also send us a loud signal prior to its emergence in full. And we don’t have all that much additional methane noise coming from the Arctic. No indication whatsoever of such a major methane perturbation in the Arctic at this time although the upper latitudes do have more atmospheric methane overall, which continues to be disturbing but not outright alarming in this regard.

          In the above map. We see various methane hotspots. The major peaking sources at present appear to be wildfires (Arctic wildfires are a pretty strong signal), wetlands in the tropics, traditional fossil fuel emitting and extraction regions, drought regions, Svalbard (which has a hydrate seep), and the Laptev. ESAS is pretty calm at the moment. In any case, none of these methane perturbations are markedly outside the ranges I’ve observed over the past five years. A very large and globally significant signal coming from ESAS consistently, one that warps all the major monitors, would confirm S&S. There is a consistent signal that is regionally significant, but it is not in a range that wags the globe. Not something I would consider to be an indicator of a ramp up to this kind of big release. That may change. It may not. But, again, this observer has nothing new to report at this time.

  4. Greg

     /  August 8, 2017

    Thank you Robert for digesting this dense report. Few of us have the time and confidence to read and fully grasp all its salient points. I wish the IPCC, indeed the whole scientific community, had a language for the public that would grab. I simply don’t remember, nor respond, to RPC 8.5, but do respond and remember “no change in course and resulting possible extinction” or “catastrophic” or similar familiar and accessible language.

    Reply
  5. wili

     /  August 8, 2017

    Thanks for the hat tip, and of course for handling in your expert way this important and disturbing development.

    Reply
  6. Abel Adamski

     /  August 9, 2017

    I note even Heartland has the report on it’s site, with a download button for the PDF

    Reply
  7. Andy_in_SD

     /  August 9, 2017

    How is this for things gone awry?

    A ‘Massive’ Wildfire Is Now Blazing In Greenland

    http://www.npr.org/sections/thetwo-way/2017/08/08/542305822/photos-a-massive-wildfire-is-now-blazing-in-greenland

    Reply
  8. Abel Adamski

     /  August 9, 2017

    OT, but of interest
    https://www.theguardian.com/science/2017/aug/07/nanochip-could-heal-injuries-or-regrow-organs-with-one-touch-say-researchers

    A novel device that reprogrammes skin cells could represent a breakthrough in repairing injured or ageing tissue, researchers say.

    The new technique, called tissue nanotransfection, is based on a tiny device that sits on the surface of the skin of a living body. An intense, focused electric field is then applied across the device, allowing it to deliver genes to the skin cells beneath it – turning them into different types of cells.

    That, according to the researchers, offers an exciting development when it comes to repairing damaged tissue, offering the possibility of turning a patient’s own tissue into a “bioreactor” to produce cells to either repair nearby tissues, or for use at another site.

    Reply
  9. Abel Adamski

     /  August 9, 2017

    Interesting article re India and coal and CO2

    https://au.finance.yahoo.com/news/indias-wild-energy-trends-raise-060008951.html

    NEW DELHI (AP) — Within the wild energy market of the world’s second-most populous nation, predictions are proving tricky. India had been projected to become a carbon-belching behemoth, fueled by thermal power plants demanding ever more coal for decades to come.

    Now, some analysts are saying that may not happen.

    NEW DELHI (AP) — Within the wild energy market of the world’s second-most populous nation, predictions are proving tricky. India had been projected to become a carbon-belching behemoth, fueled by thermal power plants demanding ever more coal for decades to come.

    Now, some analysts are saying that may not happen.

    But thanks to plunging costs for solar and wind energy, and high enthusiasm for hydropower, renewable energy generating capacity is expanding by 20 GW a year, toward a goal of 175 GW by 2022. Buckley calculates that could cut annual growth in coal demand further down to as little as 2.5 percent.

    By washing coal before it’s burned, India’s power plants now burn less to produce the same amount of power. India is also now policing rail shipments more rigorously to reduce coal theft. And new plants are required to use so-called supercritical technology that further raises the efficiency of coal burned while also reducing pollution.

    Thanks to such efficiency boosting measures, the amount of coal needed to deliver a 6 percent rate of growth in electricity demand will drop even further, and may be near flat, Buckley says.

    Other analysts agree the trends are encouraging.

    “Energy efficiency in India is moving much faster than anybody thought,” said Ajay Mathur, director of The Energy and Research Institute in New Delhi.

    Reply
  10. bostonblorp

     /  August 9, 2017

    Excellent post as always RS. So troubling to see the temperature increase is already above RCP 8.5. I know it’s early in the graph’s projections but the more we deviate from a lower emissions scenario the more extreme (and unlikely) the measures required to “bend the curve.”

    To your comment that CO2 ppm growth rate should back off a bit in 2017 it would the seem the preliminary answer is “a touch.” Mauna Loa’s July average is 2.7ppm vs a year prior. Not quite the 3ppm of 2016-2017 but still higher than the average (2ppm) for 2000-20015.

    Reply
    • That range is still very concerning. We haven’t had a proper La Nina, but to get back to 2.2 ppm per year (prior average), you need two years at approx 1.5 ppm per year. Even if 2017 backs off to 2.5 ppm, the three year average indicates a likely acceleration. I’m still pretty confident that 2017 will back off from 3 ppm per year. I’m not so confident that the recent trend doesn’t indicate an acceleration in the rate of atmospheric CO2 accumulation.

      RE methane, we did get a bump in the rate of atmospheric growth for that ghg around 2008. The present rate is slightly lower than peak rates of accumulation during the 80s and 90s. Both fracking and various environmental feedbacks probably played a role in the renewed, if somewhat slower at present, atmospheric methane accumulation.

      Reply
  11. wili

     /  August 9, 2017

    A thoughtful take on a topic that comes up once in a while:

    “When optimism spells disaster…”

    https://mahb.stanford.edu/blog/optimism/

    Extract: “One of the most dangerous threats to the human future in this, the Age of Perils, is … optimism.

    To overcome them humanity doesn’t need optimism or pessimism. It needs to exercise a singular attribute that has stood us in good stead for over a million years: wisdom.”

    Reply
    • Wisdom in the present situation involves mass mobilization to reduce carbon emissions. This involves reworking economic systems to optimize for sustainability and reduced externality. Growth in sustainable industries should be the focus of investment and capitalization going forward — not harmful forms of growth like fossil fuel burning. Primarily, growth in wind, solar, and EVs. Wisdom also involves continuing to increase efficiency. But efficiency and constraint alone can’t solve this problem. A wise person would recognize that we need to change what the larger economic system is optimized to do. A wise person would realize that if we crush it instead, it will be unable to change. That the fragmented bits would reactionarily cling to the old ways of doing things (fossil fuel burning). Wisdom involves finding the third way forward.

      Reply
  12. wili

     /  August 9, 2017

    More on the heat and fire consuming more and more of the West:

    “The new normal: Fires, devilish heat waves, and flash floods

    Wildfires haven’t just been confined to the far north this year either. In the U.S., 5.9 million acres have burned in fires so far in 2017, mainly across the West, which is 1.9 million acres above the past decade’s annual average amount. As of Monday morning, firefighters were battling 11 large blazes in California alone, with additional large fires burning in Idaho, Montana, Nevada, Oregon, Washington, and Wyoming. ”

    http://mashable.com/2017/08/08/summer-weather-on-steroids-wildfires-heat-waves/#Op_PNmbgVsqA

    Reply
  13. Spike

     /  August 9, 2017

    I notice a number of scientific journals now come with “plain language summaries”, which I think commendable, even if a scientists idea of plain language would still sail way over the head of many people in the U.K. and I suspect much of the rest of the Anglosphere – I say this as someone whose job involved translating complex science into everyday understandable language for the public. It’s a shame these reports don’t do likewise, because they tend not to reach the average man or woman due to their size, complexity and media disinterest and distortion as well as denialist lies.

    Many people will bleat with anger, surprise, and “why weren’t we told” when radical discontinuities and previously unheard of disasters strike in coming decades, and as human civilisation teeters on the brink. At present we just get hints of this, such as the 4-6 weeks worth of rain that is falling today on eastern England, the BC fires, the Italian drought and so on. As you point out much much worse is to come.

    Thanks for the effort you’ve taken summarising this Robert.

    Reply
    • Thanks for the kind words, Spike. It’s a crazy world we’re entering. People really don’t know what they’re in for. Even the best science isn’t perfectly clear on the matter. But we do know that things will keep getting worse even if we do respond. The key now is containing the damage and finding a way out.

      Reply
    • That is quite a sobering report. I looked at it, and realizing that it was almost 700 pages quickly knew that with my zero science background I could never get through it. Then I noticed on the index an “Executive Summary”, I was able to read it, and with Robert’s blog that explained even more, (i.e. the “compound events” illustration) I gained at least a basic understanding. It should be required reading for everyone. I hope the report becomes a “hot” news item.

      Reply
  14. wili

     /  August 9, 2017

    The linked reference uses model projections to demonstrate that relatively large and rapid obduction (re-emergence) of anthropogenic carbon into the well-mixed surface layer in the ocean will contribute to limiting of future ocean uptake of carbon from the atmosphere. This is not good news:

    Katsuya Toyama et. al. (2017), “Large Re-emergence of Anthropogenic Carbon Into the Ocean’s Surface Mixed Layer Sustained by the Ocean’s Overturning Circulation”, Journal of Climate, https://doi.org/10.1175/JCLI-D-16-0725.1

    http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-16-0725.1?utm_content=buffer00f0c&utm_medium=social&utm_source=twitter.com&utm_campaign=buffer

    Abstract: “We evaluate the output from a widely used ocean carbon cycle model to identify the subduction and obduction (re-emergence) rates of anthropogenic carbon (Cant) for climatological conditions during the World Ocean Circulation Experiment (WOCE) era in 1995 using a new set of Lagrangian diagnostic tools. The principal scientific value of the Lagrangian diagnostics is in providing a new means to connect Cant re-emergence pathways to the relatively rapid renewal timescales of mode waters through the overturning circulation.

    Our main finding is that for this model with 2.04 PgC/yr of uptake of Cant via gas exchange, the subduction and obduction rates across the base of the mixed layer (MLbase) are 4.96 PgC/yr and 4.50 PgC/yr, respectively, which are twice as large as the gas exchange at the surface. Given that there is net accumulation of 0.17 PgC/yr in the mixed layer itself, this implies the residual downward Cant transport of 1.40 PgC/yr across the MLbase is associated with diffusion. Importantly, the net patterns for subduction and obduction transports of Cant mirror the large-scale patterns for transport of water volume, thereby illustrating the processes controlling Cant uptake. Although the net transfer across the MLbase by compensating subduction and obduction is relatively smaller than the diffusion, localized pattern of Cant subduction and obduction implies significant regional impacts. The median timescale for re-emergence of obducting particles is short (less than 10 years), indicating that re-emergence should contribute to limiting future carbon uptake through its contribution to perturbing the Revelle factor for surface waters.”

    Thanks to aslr at asif, as often, for text and link

    Reply
  15. So here’s the current status of fixing our problem: 1) Paris, if met, is not sufficient for meeting our goals and, 2) Paris is not being met currently. Nice work. Let’s agree to weak goals and then fail to meet them.

    Reply
    • Joe — I’ve got to say I agree with most of what you’ve posted on Twitter. That said, I think that you are counter-productively attacking the wrong article here. International treaties are not dictatorships and thus must move forward by consent. Paris was the best we could have reasonably hoped for at the time. We should support it. But we are right to demand more.

      In essence, Paris is the strongest climate treaty yet. Its goals were the most ambitious ever presented.

      To understand Paris, you have to also understand its overarching or visionary goals and its committed goals. The visionary goals of Paris were to set up a framework that ultimately contained warming to 1.5 to 2 C. The authors recognized that these goals would not immediately be committed to but it secured this pledge from member nations.

      In setting up a pathway to try to hit 2 C warming or less, nations committed to certain carbon reductions. These voluntary reductions were first commitments (NDCs) with the implicit notion that nations would continue to build on these commitments. The net effect of present NDCs would be reducing warming from a BAU path of 5-9 C warming to around 3 C warming.

      Presently, not all nations have fully enacting NDCs, this puts us on a 4 C pathway or thereabouts.

      Adding complexity to this issue is the fact that climate sensitivity is somewhat uncertain. If we look at paleoclimate, present levels of greenhouse gasses get us to close to 2 C by end Century. So if paleoclimate sensitivity ends up being correct, then we actually need to reduce atmospheric greenhouse gasses from present levels to avoid 2 C.

      The end message that should come from this understanding is the need for renewed urgency. But we should also understand that attacking Paris is dramatically harmful. That when you attack Paris, you implicitly support continued fossil fuel burning and the climate harms that will ultimately follow. That’s not a position that you or I want to be in. The stronger position is to support Paris, but to push for a strengthening of the treaty’s goals.

      Since Paris enables nations to rapidly reduce carbon emissions, we should support the treaty. But we should also point out that Paris goals need to step up considerably if we are to have any hope of missing 2 C warming. That said, even if we fail to avoid 2 C, we will, by enacting Paris and working to improve it, have prevented many degrees of additional warming that otherwise would have happened and have prevented a far more serious degree of global harm.

      In the future, I would appreciate it if you moderated your statements a bit, stepped away from simplistic arguments without attempting to understand how policies work, and stop attacking helpful global policies that will ultimately save millions of lives but that need further support and refinement to actually meet stated goals.

      Reply
  1. Revenge of The Climate Scientists | As My World Turns

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