Current fossil fuel infrastructure does not yet commit us to 1.5 °C warming

From Nature

Abstract

Committed warming describes how much future warming can be expected from historical emissions due to inertia in the climate system. It is usually defined in terms of the level of warming above the present for an abrupt halt of emissions. Owing to socioeconomic constraints, this situation is unlikely, so we focus on the committed warming from present-day fossil fuel assets. Here we show that if carbon-intensive infrastructure is phased out at the end of its design lifetime from the end of 2018, there is a 64% chance that peak global mean temperature rise remains below 1.5 °C. Delaying mitigation until 2030 considerably reduces the likelihood that 1.5 °C would be attainable even if the rate of fossil fuel retirement was accelerated. Although the challenges laid out by the Paris Agreement are daunting, we indicate 1.5 °C remains possible and is attainable with ambitious and immediate emission reduction across all sectors.

Introduction

The Paris Agreement includes the aim to pursue efforts to limit global mean temperature rise to 1.5 °C above pre-industrial levels1. How close we are to 1.5 °C depends on the choice of reference (pre-industrial) period, the methods of generating global mean temperatures from historic records2 and whether the human-induced warming contribution is isolated from the naturally forced warming and internal variability3,4.

The zero emissions commitment4,5,6 refers to the level of further warming that will occur if emissions abruptly cease, and is related to geophysical inertia. In previous studies, the long-term zero emissions commitment ranges from around −0.4 to +0.9 °C, and is sensitive to the carbon cycle response7,8, ocean heat uptake9, magnitude and pathway of historical warming10, and whether or not non-CO2 forcing is included10,11. When non-CO2 forcing is included, setting emissions to zero leads to an initial rapid warming, associated with the removal of short-lived cooling aerosols, followed by a slower decline and stabilisation of temperatures driven by a reduction in the concentrations of short- and long-lived greenhouse gases8.

An alternative assessment of committed warming is an infrastructure commitment12,13,14,15. This combines geophysical commitment concepts with knowledge of the possible speed at which fossil fuel-emitting infrastructure could be phased out. Under an infrastructure commitment, global society makes a serious effort to phase-out greenhouse gases but does not go as far as decommissioning power plants and other infrastructure before the end of their expected lifetimes (central estimate of 40 years for fossil fuel power plants)12,13. Transitioning to a zero carbon energy system within 40 years will be politically and societally challenging, and opinions are divided on whether this may be technically and economically possible16,17,18,19,20. We do not seek to assess the practical feasibility of this transition, but merely to report on the consequences in the context of keeping global mean temperature rise below 1.5 °C.

A third type of commitment that is often analysed is a constant forcing21,22 or constant composition commitment, which is defined as the further warming that would result if atmospheric composition and hence radiative forcing were held fixed at today’s values. Under such a scenario, temperatures continue to increase, with the rate of warming slowing down as equilibrium is approached22. The constant forcing commitment is not directly relevant to assessing warming committed from possible real-world mitigation scenarios, as constant forcing simulations require a continually declining but finite net greenhouse gas emission and would be hard to engineer. No known emission strategy gives constant forcing. Such constant forcing simulations have led to the misconception that inertia within the ocean system means that significant future warming is inevitable6.

In this work, we explain that committed warming from present-day fossil fuel infrastructure is below 1.5 °C in 64% of an ensemble of scenarios with a simple climate model. These results are on the basis of fossil fuel assets starting to be retired from the end of 2018 once they reach the end of their design lifetimes, and accounts for the age distribution of extant stock. We focus on the energy generation, transport and industrial sectors which have the best data available for historical lifetimes and cover 85% of global emissions. The remaining 15% of global emissions are assumed to follow the retirement curves of the energy sector, as fewer data are available and in many cases there are cross-overs (for example, electricity supply and domestic heating). The phase out is such that the majority of CO2 emissions have been eliminated in 40 years. As fossil fuel combustion emits short-lived climate forcers (SLCFs, which tend to result in a net negative forcing dominated by aerosol cooling) alongside CO2, and both are gradually reduced in an infrastructure phase-out scenario, there is no sudden increase in warming from reducing emissions gradually. This is in contrast to a zero emissions commitment, where the elimination of short-lived pollutants suddenly uncovers longer-lived greenhouse gas warming.

Discussion

In this paper, we show that limiting warming to 1.5 °C is not yet geophysically impossible. Exceeding 1.5 °C occurs in only 9% of ensemble members under a zero emissions commitment if emissions cease at the end of 2018. Even if current fossil fuel infrastructure is retired at end of its lifetime and not replaced, it is possible to limit warming to 1.5 °C (bar the possibility of strongly amplifying carbon cycle feedbacks such as permafrost melt or forest dieback). Both reductions in CO2 and other greenhouse gases are needed in order to take us close to such a temperature outcome. Aerosols exhibit a net cooling effect in the present day11 but are co-emitted with greenhouse gases59 and tropospheric ozone precursors. Although a gradual reduction of emissions from phasing-out fossil fuels does not result in a sudden warming, near-term (peak and 2050) warming commitments do depend strongly on the level of present-day aerosol forcing. End-of-century warming commitments depend on aerosol forcing, but with an important contribution from ECS and TCR.

The simple climate model used in our analysis may underestimate committed warming owing to possible future increases in climate sensitivity, as it employs a climate sensitivity that is invariant in time. Under a shifting pattern of surface warming through time60, climate sensitivity over the historical period may have been lower than we can expect in the future as both the Eastern Pacific and Southern Ocean have not yet experienced strong warming4,61,62. Our simple model includes the biogeochemical feedbacks of decreasing carbon sink efficiency with increasing temperature and increasing biospheric and ocean carbon uptake63, but may exclude possible other biogeochemical feedbacks where the elevated temperatures might affect future Earth system processes and carbon cycle response64,65. These feedbacks are expected to play out at timescales of decades to centuries and may thus be of limited relevance for estimating the committed warming over the 21st century. In this instance our results provide a useful first-order estimate of committed warming based on current knowledge. Our findings contrast with a recent study by Pfeiffer et al.15, which suggest that the infrastructure commitment from the energy sector alone is enough to commit us to warming above 1.5 °C. However, their analysis is based on allocating a share of the remaining carbon budget to 1.5 °C to energy sector emissions and does not discuss non-CO2 emissions or pathways in non-energy sectors. The challenge of making emission reductions across many sectors and countries remains very high but our committed warming scenarios show two important insights. First, geophysics does not yet commit the world to a long-term warming of > 1.5 °C. Second, even when phasing out existing CO2-emitting infrastructure at the end of its expected lifetime, warming is also kept to below 1.5 °C (or 0.4 °C warmer than today) with > 50% probability, whereas delaying action until 2030 reduces this probability to below 50%. This is important information, as it shows that whether global mean temperature increase will be kept to below 1.5 °C depends on societal choices made today and emissions reductions implemented over the coming decades.

Read the full paper here.

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32 thoughts on “Current fossil fuel infrastructure does not yet commit us to 1.5 °C warming

  1. Similar to the above article, James Hansen has dialed things back in terms of the necessity of quick action.

    The ponderous response of the climate system also means that we don’t need to instantaneously reduce GHG amounts. However, despite uncertainties about some climate processes, we know enough to say that the time scale on which we must begin to reduce atmospheric GHG amounts is measured in decades, not centuries. Given the fact that the fastest time scale to replace energy systems is decades, that means that we must get the political processes moving now. And that won’t happen until the public has understanding of what is actually needed and demands it. link

    The actual science doesn’t support CAGW alarmism. People are starting to notice.

    • ” that won’t happen until the public has understanding of what is actually needed and demands it.”
      _____________________________________________________

      Worst-case

      – the public has no understanding of what is actually needed and demands the contrary.

      – the public has vague understanding of what is actually needed and therefore demands ~ something.

  2. Someone needs to inform them that there is one sect of their Climate religion that it is too late:

    Have We Passed the Point of No Return on Climate Change?
    – April 13, 2015, Scientific American mag.
    https://www.scientificamerican.com/article/have-we-passed-the-point-of-no-return-on-climate-change/

    (in that junk science puff piece from Sci-Am, they actually are advocating GreenPeace’s alarmism junk science claims on CO2 and climate. So very Sad. A complete abandonment of science.)

    We apparently crossed the Climate Rubicon 4 years ago according to SciAm. These dweebs now writing Nature mag just haven’t gotten the memo from their fellow Climate Cultists it’s Game Over. The Earth cooked to state:dead almost 4 years ago.

    Apparently, in 2015 the threshold was 400 ppm. Earth was gonna fry after that.
    But in the early 1990’s it was a 350 ppm as the threshold to fry the Earth. Hence Weepy Bill McKibben’s 350 organization, as he milked the casue for money as a true climate hustler for his paycheck and his day in the limelight.

    Now, the next PONR (point of no return) is 450 ppm. Today, according to the climate priests 450 ppm too will bring about the 4 Horsemen of the Apocalypse on humanity. At least until it passes with nothing happening.

    The goal-post shifting will never end as each milestone is attained and nothing happens. The climate hustlers’ paychecks depend on spinning the next climate horror stories Ad Nauseum.

    And it all is aided and abetted with the dumbing-down the public education system to help them achieve their alarmist goals towards global socialism via a science ignorant populace willing to trade nothing in return for their freedoms and economic prosperity.

    • +1 Joel.
      The boy who cried wolf. For the last what, 20+ years? Each year the tipping point, global collapse, end of days….. Just as in the story people are becoming numb to the message. Real Clear Energy keeps running those horror stories as written by solar and wind lobbyists while holding their hands out for the free government cash.
      And you have called it right. A public education system that has stopped teaching students how to think, reason and question. You WILL be assimilated.

  3. So what do you do if you claim to be an expert on a subject, make a projection based on your expertise, and it doesn’t happen when the time comes? You panic and double down on your expertise and make more projections. What have you got to lose? These people need to be outed.

  4. You gotta love these kind of assumptions:
    “Our simple model includes the biogeochemical feedbacks of decreasing carbon sink efficiency with increasing temperature and increasing biospheric and ocean carbon uptake63, but may exclude possible other biogeochemical feedbacks where the elevated temperatures might affect future Earth system processes and carbon cycle response…”

    That statement is itself self-contradictory. So temps are increasing (granted), and biosphere and ocean carbon sinks are increasing (provable), but apparently in their view “efficiency” is going down?

    There are two main carbon sinks on a scale of years; the oceans and biologic. The biologic sink operates on an annual scale, we see it in the seasonal saw-tooth of mostly a NH CO2 up and down pattern. The ocean carbon (CO2) uptake we see in the MLO CO2 rate with regards to the ENSO swings. And the efficiency of both are currently increasing in efficiency with temperature in the range under consideration (temperate Earth).

    As for relevance, the carbon sink of most relevance is the biologic sink, and it is increasing, and it will markedly increase in capacity as temperatures increases in the mid- to higher-latitudes (greening Earth) with longer growing seasons in a warmer world. So there decreasing efficiency assumption is invalid from the start. The oceans also have huge biologic sink called phytoplankton. And that sink is just getting warmed up in its sink rate as CO2 fertilization and higher overturning will bring them nutrients to sequester carbon to depth as they sink into the abyss.

    These guys assumptions are so wrong. They use their assumptions to (circularly) establish their conclusion. But take apart their assumptions and break their circle of assumptions and their claims collapse.

    Climate Science has so much junk pseudoscience in it now, it is sad that these guys can even write this stuff and still sleep at night with themselves. I guess if it brings in the paycheck… and pays the mortgage if the rationale.

  5. Why oh why is the mantra still “limit global mean temperature rise to 1.5 °C above pre-industrial levels”?
    What was so perfect about pre-industrial times?
    What’s so bad about current temperatures?
    Now tell me again how a 0.5°C rise above current temperatures will be catastrophic.

    • The 1850’s were only just coming out of the Little Ice Age. Every policy these people promote it an attempt to push us back into them: no fossil fuels, no plastics, no antibiotics (yes, a lot of people are trying to stop us from using antibiotics).

  6. … a 64% chance …

    Bless their little hearts!

    I’d been thinking there was a 97% chance the ocean would boil away before I saved enough money for that world cruise. This gives me hope. I’ll keep on saving.

    • I love the precision! If you have a simplified model, your risk assessment of 64% is really 60% plus or minus something.

      The 64% is designed to appeal to journalists and other leftists who think political science is a science.

  7. “These results are on the basis of fossil fuel assets starting to be retired from the end of 2018 once they reach the end of their design lifetimes, and accounts for the age distribution of extant stock.”
    This statement and the whole paper is predicated on the erroneous assumption that fossil fuel emissions control and in fact partially remain in the atmosphere while natural emissions of over 30 times as much of the same molecule don’t. The evidence and analysis of fossil fuel emissions indicate that they cause an insignificant increase on atmospheric CO2. If this empirical relationship doesn’t change we cannot expect reducing emissions to have a measurable effect. Fossil fuel CO2 is the same as other CO2 and must react within the climate system the same as any other source. For fossil fuel CO2 to cause a build up in the atmosphere the sinks must be nearly saturated and and sum of all the natural sources must be nearly constant. There is no evidence of either of these conditions existing.

  8. you cannot control the earth temperature by limiting something that doesn’t control the earth temperature

  9. The simple climate model used in our analysis may underestimate committed warming owing to possible future increases in climate sensitivity, as it employs a climate sensitivity that is invariant in time. Under a shifting pattern of surface warming through time60, climate sensitivity over the historical period may have been lower than we can expect in the future as both the Eastern Pacific and Southern Ocean have not yet experienced strong warming

    This is interesting, and its one of the critical points. A lot of the argument above is to the effect that climate sensitivity falls with increasing temperatures, and people propose a lot of different ways this could happen. If it does, it will make warming to some extent self limiting.

    I haven’t come across any evidence to show either way, but it seems unlikely that sensitivity is constant as temperature rises. Or, indeed, as it falls. Because of all the feedbacks mentioned in the comments.

    The other interesting thing here is a familiar note. The people who would have to stop installing new fossil fuel emitting stuff are in China and India. One of the characteristic themes of activist writing on this subject is the failure to define who has to take action to achieve what is proposed.

    There is a general invocation of ‘we’. ‘We’ have to run down our fossil fuel consumption starting now. If ‘we’ do it, we can still save the planet.

    But they never say who has to do what in order to do this. The one thing that is an absolute taboo is any suggestion that China and India and so on will have to first freeze and then reduce their emissions.

    Next time you read a discussion of this, point out that the goals that ‘we’ must achieve cannot be met without China and India actually reducing the tonnage they emit.

    Then watch the debate immediately move without missing a beat to saying that its only fair that they should carry on emitting and increasing. Because exports, per capita, installing wind and solar, historical emissions.

    In a flash, the fact that their emissions are dooming civilization as we know it will have vanished and you will find yourself shaking your head and wondering what happened. Where did that all go?

    How did we start out trying to save the planet by reducing emissions, only to find ourselves explaining that its only fair China and India should increase enough to doom civilization?

  10. If we deploy the world’s entire intellectual capacity, we can realize within twenty years that total hydrocarbons can be removed if combined with geoengineering, fusion and LENR technologies.

    • Finding enough “intellectual capacity” would put an end to this dark ages meme. It’s the Stoopid that keeps it going.

  11. “It is usually defined in terms of the level of warming above the present for an abrupt halt of emissions. Owing to socioeconomic constraints, this situation is unlikely, ”

    Unlikely? UNLIKELY??? I believe the word they’re looking for is “impossible.” It sounds like prevention is a losers strategy, and even if you accepted everything they believed about the coming climate disaster, we should instead save our resources for adjusting to the global climate cycle.

  12. Having begun my personal study of human nature and and how we go about things over 80yrs ago, I want to advise that NOTHING will be done about this wifty poofty issue. Some liken it to a world war that we must marshal our forces to prevail on the side of GOOD. Well such folk havent experienced a world war. The invasion of Poland and the bombing of Pearl Harbour is the sort of thing that causes people to consider marshalling their forces.

    Worry warts writing papers and studies and creating faculties in unies to report that a world war is coming, won’t result in the marshalling of forces. When they are highly paid and decorated, and fêted, and schmoozed by Hollywood for this work, no marshalling of forces will result. Even with the NUTSY war machine rolling towards invasion, Foreign Secretary Chamberlain of Britain after meeting with Chancellor A. Blitzler said no marshalling of forces was necessary. No this World Warmer I will simply die out with heaps of rationalization diversion, revision of history, retirements and taking down of signs.

  13. The critical question is not whether existing fossil fuel burning sources can be simply turned off at the end of their useful life. That could certainly be done. The critical questions are what energy sources replace those fossil fuel ones; can those be reasonably constructed over the next few decades’ what would that cost the world, not only in capital, but also in failure to fund other essential activities; are sufficient raw ingredients available (e.g. rare metals for solar & wind power) and can they be mined and incorporated into renewable energy sources without fossil fuel power. The over-riding question is what would occur with the world’s current living standard and would the world’s citizens view any major decline as preferable over predicted future warming risks from the climate community? Unless that question is answered ‘yes’ such changes are unlikely to occur.

  14. If climate science had the forecasting and modeling ability they claim to have, they would all be working on Wall Street. The very fact Goldman Sach hasn’t been pulling climate scientists way from the University pretty much proves the most informed people in the world don’t believe the nonsense, and they know garbage models when they see them. The most simple explanations are usually the best, and Climate Alarmists do their best to unnecessarily complicate the issue.
    CO2 Can’t Cause Catastrophic Warming as Long as El Niño, La Niña and Hurricanes Exist
    https://co2islife.wordpress.com/2019/01/19/co2-cant-cause-catastrophic-warming-as-long-as-el-nino-la-nina-as-well-and-hurricanes-exist/

    Also, can anyone point to a controlled experiment where it has been proven that LWIR between 13 and 18 microns can even warm water? Someone needs to do an experiment using LWIR and visible radiation and measure the temperature change. If LWIR between 13 and 18 microns can’t penetrate or warm water, all this effort is for naught.

  15. Current fossil fuel infrastructure does not yet commit us to squadrons of flying pigs or space alien invasions either.

  16. I have a hypothetical question. Isn’t Science and technology supposed to make life more enjoyable? If so, why do I have to spend so much time trying to glean thru all the technical hogwash only to find the scum of this earth are living better than the working class?

  17. The impression that I get from reading the official press release is that it is “Damage Controll”
    “Please member s of the general public, we are doing our best to help you, but we need more money or our lifestyle will suffer. One almost feels sorry for them, the true believers will really be suffering.

    MJE

    • Some AGW may be here. Mauna Loa ppm data is prima facia case justifying subsidies of alternative enervy and incentives to alter consumer behavior but not massive transfers of wealth and demonization of ff industry that has made and must continue for decades to made our modern society and economy work and deliver basic essentials for personkind. If climate change activists would recognize that people must have reliable 24-hr energy at current price
      ranges and begin planning for adoption to reasonBle
      assumptions and stop lying about false connections to weather, etc., perhaps we could make progress.

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