Summary: Scientists and journalists bombard us with news about the coming climate catastrophe, described as certain unless we drastically change our economy. This has plunged many into despair. The hidden key to these forecasts is RCP8.5, the worst case scenario of the IPCC’s Fifth Assessment Report — often erroneously described as the “business as usual” scenario. Understanding this misuse of science reveals the weak basis of the most dire warnings (which set the mood at the Paris Conference), and helps explain why the US public assigns a low priority to fighting climate change despite the intense decades-long publicity campaign.
“We’re going to become extinct. Whatever we do now is too late.”
— Frank Fenner (Prof emeritus in microbiology at the Australian National U); Wikipedia describes his great accomplishments), an interview in The Australian, 10 June 2010.
In the IPCC’s Fifth Assessment Report four scenarios describe future emissions, concentrations, and land-use. They are Representative Concentration Pathways (RCPs), the inputs to climate models that generate the IPCC’s projections. Strong mitigation policies lead to a low forcing level of 2.6 W/m2 by 2100 (RCP2.6). Two medium stabilization scenarios lead to intermediate outcomes in RCP4.5 and RCP6.0.
RCP8.5 gets the most attention, with its bold and dark assumptions (details here). It is a useful and important scenario, a warning of what might happen if the 21st century goes badly. It should spur us to act. The UK Met Office said that “despite not being explicitly designed as business as usual or mitigation scenarios” (update: it is a dead link; they archived posts but not reports here). Nonetheless, RCP8.5 has often been misrepresented as the “business as usual” scenario — becoming the basis for hundreds of predictions about our certain doom from climate change.
The result of this (part of a decade-long campaign) is widespread despair among climate scientists and more broadly, among Leftists. This misuse of RCP8.5 is a triumph of propaganda, but polls show its ineffectiveness (with climate change ranking at or near the bottom of public policy concerns). Yet each month brings more of the same.
What future does RCP8.5 describe?
“In 2002, as I edited a book about global climate change, I concluded we had set events in motion that would cause our own extinction, probably by 2030. I mourned for months …”
— “Apocalypse or extinction?” by Guy McPherson (Prof Emeritus of Natural Resources and Ecology, U AZ), October 2009. He is the author of Extinction Dialogs: How to Live with Death in Mind (2014).
The RCPs each describe one path to achieving these rates of forcing. The papers describing the RCP’s clearly state their assumptions, allowing us to assess their likelihood and consider specific ways to prevent them. Unfortunately most papers using the RCPs (usually RCP8.5) to warn us of coming climate catastrophes do not do so. This means their discussion of the need to prevent those emissions are unfounded, as are their recommendations of ways to do so.
RCP8.5 describes a bleak scenario, a hot and dark world in 2100 (since it’s powered by coal, perhaps literally dark) — even before considering the effects of climate change. Below are the key points, with graphs from “The representative concentration pathways: an overview” by Detlef P. van Vuuren et al in Climatic Change, Nov 2011.
RCP8.5 assumes breaks in long-term trends for population growth and technological change, the opposite of the usual base case for planning. See this post for a more detailed look at it.
Rapid population growth and slow economic growth in RCP8.5
RCP8.5 assumes a doubling of Earth’s population to 12 billion by 2100, which is the high end of the current UN forecast. The UN gives a purely probabilistic forecast, not considering if the numbers are realistic. For example, this assumes the population of Africa grows from one billion to 5 billion, giving it a density roughly equal to that of China today (which requires a highly ordered society to survive). Nigeria’s population would rise from today’s 160 million to almost 1.5 billion in 2100. Possible, but hardly “business as usual”.
While population skyrockets, GDP would drastically slow — producing a massive increase in world poverty (reversing the trend of the past several decades).
Slow tech growth in RCP8.5 takes us back to a 19thC world
RCP8.5 assumes a slowing of technological innovation, most clearly seen in energy use. By 2100 energy efficiency has improved only slightly (reversing the current decades-long trend), so that despite GDP being one-third lower than under RCP2.6, energy consumption is over twice as large. Worse, we will have gone back to a 19th C-like future where the world in 2100 is powered by coal. This is possible, but not a “business as usual” scenario.
Update: Recognition of this is even appearing in the peer-reviewed literature. For example, see this in “Why do climate change scenarios return to coal?” by Justin Ritchie and Hadi Dowlatabadi in Energy, 1 December 2017 (gated).
“[E]vidence indicates RCP8.5 does not provide a physically consistent worst case BAU trajectory that warrants continued emphasis in scientific research. Accordingly, it does not provide a useful benchmark for policy studies.”
How did RCP8.5 come to describe a “business as usual” future?
“With business as usual life on earth is largely doomed.”
— John Davies (geophysicist, senior research at the Cold Climate Housing Research Center), 22 February 2014.
This useful scenario was hijacked to serve the apocalyptic visions of activists. Did this happen from scientists’ deliberate misrepresentation (a noble lie?) or carelessness? Who can say? Here are some examples of climate scientists misrepresenting RCP8.5.
- Mis-stated in the beginning: “Compared to the scenario literature RCP8.5 depicts thus a relatively conservative business as usual case with low income, high population and high energy demand due to only modest improvements in energy intensity.” From “RCP 8.5: A scenario of comparatively high greenhouse gas emissions” by Keywan Riahi et al in Climate Change, November 2011.
- “RCP8.5 assumes a ‘business-as-usual’ approach.” From a guide to AR5 WG1 by Carolyn Symon (PhD, environmental science), by Cambridge U (Sept 2013).
- “The scenario with the most warming is the ‘business-as-usual’ RCP8.5, in which global mean temperature could be 4°C or more above pre-industrial times.” By Matt Collins (Prof, Climate Systems at Exeter U) at Climatica, Dec 2013.
- “Under a business as usual trajectory, the IPCC is saying 3.7 to 4.8 degrees by the end of this century“, said by Lesley Hughes (Prof Biology at Marcqarie U, lead author of WG2 in AR4 & AR5), March 2014.
- Ottmar Edenhofer (Prof at the Potsdam Inst, Co-Chair of WG3 for AR5) describes RCP8.5 as the “business as usual” scenario at the IPCC AR5 WGIII press conference, 13 April 2014.
- “What we see so far is that the only business-as-usual scenario among the RCPs is RCP8.5, a high-end business-as-usual scenario.” Said by John Nielsen-Gammon (Texas State Climatologist, Prof Atmospheric Sciences at Texas A&M), August 2014.
- “for business-as-usual greenhouse gases (RCP8.5 scenario) …” — Said by James Hansen (climate scientists, Columbia Earth institute), July 2015.
- “RCP8.5 is a scenario with unmitigated rise in greenhouse gas emissions.” — Said by Stefan Rahmstorf (Professor of Physics of the Oceans, Potsdam U) at RealClimate (Aug 2015). That’s true, but misleading by not mentioning the other assumptions.
Tales of nightmares based on RCP8.5
RCP8.5 became the basis for scores of studies describing horrific futures that appear almost inevitable (since large global public policy changes seem unlikely). But they seldom mention RCP8.5’s extreme assumptions. The following articles are examples of this year’s crop: most are from the past 3 months — part of the campaign to build hysteria for the Paris conference.
These misrepresentations of climate science are examples of the poor conduct by scientists that has characterized the public policy campaign about climate change, and which I believe caused the campaign to fail. That doesn’t mean that climate change will not have awful consequences. Merely that we’ll be unprepared for them.
Studies misrepresenting RCP8.5, with associated articles for the public
- Government regulation (based on studies): Draft summary of the sea level rise section of regulations for New York’s Community Risk and Resiliency Act: “RCP 8.5 … is generally considered to be the “business as usual” scenario.”
- “Accelerating extinction risk from climate change” by Mark C. Urban in Science, 1 May 2015. Gated. Open copy here. “If we follow our current, business-as-usual trajectory [representative concentration pathway (RCP) 8.5; 4.3°C rise], climate change threatens one in six species (16%).”
- “End-of-century Manhattan climate index to resemble Oklahoma City today” says the hysterical press release by the Carnegie Institute about “Impacts of global warming on residential heating and cooling degree-days in the United States” by Yana Petri & Ken Caldeira (Petri is a high school student), Scientific Reports, 4 August 2015. Based, of course on RCP 8.5.
- “Interacting effects of climate change and habitat fragmentation on drought-sensitive butterflies” Tom Oliver et al, Nature Climate Change, October 2015 — “Under RCP8.5, which is associated with ‘business as usual’ emissions…”.
- “Climate change map shows Boston is an Atlantis in waiting” at the Boston Globe’s website, and the “Surging Sea Ice” interactive graphic at ClimateCentral — which describes RCP8.5 as the “unchecked pollution” scenario (no mention of rapid population growth or the tech slowdown). Both are based on “Carbon choices determine US cities committed to futures below sea level” by Benjamin H. Strauss et al, PNAS, Nov 2015 — which describes RCP8.5 as the “business as usual scenario”.
- “Future temperature in southwest Asia projected to exceed a threshold for human adaptability” by Jeremy S. Pal & Elfatih A. B. Eltahir, Nature Climate Change, February 2016 (gated) — Describes RCP8.5 as a “business as usual scenario”. Reported in Time as “These Cities May Soon Be Uninhabitable Thanks to Climate Change“.’
- “Climate outlook may be worse than feared“, U of Edinburgh press release for “Climate Sensitivity” by Roy Thompson, Earth and Environmental Science Transactions of the Royal Society of Edinburgh, December 2015 (gated). “Under a business-as-usual scenario, which assumes that there will be no significant change in people’s attitudes and priorities, Earth’s surface temperature is forecast to rise by 7.9oC over the land, and by 3.6oC over the oceans, by the year 2100.”
- “Temperature-driven global sea-level variability in the Common Era“, Robert E. Koop et al, PNAS, 23 February 2016. Gives scary forecasts based on RCP8.5, which it describes as “business as usual.” Discussed in Scientific American: “New Data Reveal Stunning Acceleration of Sea Level Rise“.
- “Future temperature in southwest Asia projected to exceed a threshold for human adaptability” by Jeremy S. Pal & Elfatih A. B. Eltahir in Nature Climate Change, Feb 2016. Examines impacts of RCP4.5 and RCP8.5. Describes the former as with “mitigation” and the latter as “business as usual”. Ungated copy here.
- “Contribution of Antarctica to past and future sea-level rise” by Robert M. DeConto & David Pollard in Nature, 16 March 2016. Straightforward analysis of implications to the RCP scenarios. Media publicity focused on the dire results from RCP8.5, seldom mentioning its assumptions.
- “Strongly increasing heat extremes in the Middle East and North Africa (MENA) in the 21st century” by J. Lelieveld et al, Climate Change, July 2016 — The high-end forecasts, which made the headlines, were from RCP8.5. They described it as a “business-as-usual” scenario. See the Phys.org article.
- “The climate response to five trillion tonnes of carbon” by Katarzyna B. Tokarska et al, Nature Climate Change, September 2016. This extrapolates the RCP8.5 scenario through 2300. It describes RCP8.5 as a “business as usual scenario… in the absence of any climate change mitigation policy”. No mention of RCP8.5’s assumption that technological progress stagnates (through 2300!), nor the likely population crash starting in the late 21st century as the current crash in fertility eventually has effect.
- “Estimating economic damage from climate change in the United States” by Solomon Hsiang et al. in Science, 30 June 2017. Describes RCP8.5 as ” business-as-usual emissions.”
- Comparing outcomes under RCP4.5 and RCP8.5: “Deadly heat waves projected in the densely populated agricultural regions of South Asia” by Eun-Soon Im et al. in Science Advances, 2 August 2017. A nicely done study. But it mischaracterizes RCP8.5 as a “business as usual” scenario. The Guardian exaggerates this study to create alarmist propaganda: “Climate change to cause humid heatwaves that will kill even healthy people“.
- “Recent very hot summers in northern hemispheric land areas measured by wet bulb globe temperature will be the norm within 20 years” by Chao Li et al. in Earth’s Future, 17 October 2017 — Uses only RCP8.5 because “the projected future temperature increase does not significantly diverge under different RCP scenarios until 2030.”
- “High Resolution Dynamical Downscaling Ensemble Projections of Future Extreme Temperature Distributions for the United States” by Zachary Zobel et al. in Earth’s Future, 20 November 2017. It accurately says only “RCP 8.5 assumes the continued heavy use of fossil fuels at a similar, or greater, rate as current concentrations of CO2 and other GHGs through the end of the century leading to a radiative forcing of 8.5 W/m2 by 2100.” Unfortunately it also describes RCP8.5 as “business as usual.”
- “Global Melting? The Economics of Disintegration of the Greenland Ice Sheet” by William D. Nordhaus, a NBER working paper (May 2018). Correctly identifies RCP8.5 as a “high warming scenario.” But it shows that RCP8.5 is similar to the baseline scenario of the author’s Dynamic Integrated Climate-Economy model (DICE).
Papers using only RCP8.5, without describing it or explaining why
These use only RCP8.5, but provide no explanation for the choice – or context describing its unlikely assumptions
- “Downscaling CMIP5 climate models shows increased tropical cyclone activity over the 21st century” by Kerry A. Emanuel in PNAS, 23 July 2013.
- “USGS Projects Large Loss of Alaska Permafrost by 2100” about a paper in Remote Sensing Systems (gated), October 2015.
- “Increasing water cycle extremes in California and in relation to ENSO cycle under global warming“, Jin-Ho Yoon et al, Nature Communications, October 2015. “Both intense drought and excessive flooding are projected to increase by at least 50% towards the end of the twenty-first century…” It uses RCP 8.5 without any description or context.
- “Finding forced trends in oceanic oxygen” by Matthew C. Long et al, Global Biogeochemical Cycles, February 2016. Ungated copy here. Uses RCP8.5, but gives no description of it. A carefully written paper, accompanied by a slightly less carefully written press release, made into sensational agit-prop by activists. Details here.
- “Projected asymmetric response of Adélie penguins to Antarctic climate change” by Megan A. Cimino el at, Scientific Reports, 16 June 2016. Based on RCP 8.5, which it describes only as “future climate model projections.”
- “Increased rainfall volume from future convective storms in the US” by Andreas F. Prein et al. in Nature Climate Change, 20 November 2017. Gated. Uses only RCP8.5. I don’t have a copy.
- “Unprecedented climate events: Historical changes, aspirational targets, and national commitments” by Noah S. Diffenbaugh et al. in Science Advances, 14 February 2018.
- “Climate models predict increasing temperature variability in poor countries” by Sebastian Bathiany et al. in Science Advances, 2 May 2018. They state that RCP8.5 is “the future scenario with the largest greenhouse gas emissions.”
- “Quantitative attribution of climate effects on Hurricane Harvey’s extreme rainfall in Texas” by S-Y Simon Wang in Environmental Research Letters, May 2018.
- “An examination of an inland-penetrating atmospheric river flood event under potential future thermodynamic conditions” by Kelly Mahoney et al in Journal of Climate, August 2018.
Progress! Studies now properly using the RCPs
- “Ocean acidification in the surface waters of the Pacific-Arctic boundary regions“, Jeremy T. Mathis et al, Oceanography, 2015 #2 — “The continental shelves of the Pacific-Arctic Region (PAR) are especially vulnerable to the effects of ocean acidification (OA) … As aragonite in these shelf seas slips below the present-day range of large seasonal variability by mid-century, the diverse ecosystems that support some of the largest commercial and subsistence fisheries in the world may be under tremendous pressure. …The future simulation followed the high-emissions representative concentration pathway (RCP) 8.5 atmospheric CO2 scenario.”
- “Divergent trajectories of Antarctic surface melt under two twenty-first-century climate scenarios” by Luke D. Trusel et al, Nature Geoscience, December 2015. This used RCP 8.5 as its high-end scenario. The Guardian reported on this in their usual alarmist fashion: “Antarctic ice is melting so fast the whole continent may be at risk by 2100” — “It showed that if greenhouse gas emissions continued at their present rate, the Antarctic ice shelves would be in danger of collapse by the century’s end.”
- “Future ozone air quality and radiative forcing over China owing to future changes in emissions under the Representative Concentration Pathways (RCPs)” by Jia Zhu and Hong Liao in GRL-Atmospheres, 27 February 2016 — Uses all four RCPs.
- “Consequences of twenty-first-century policy for multi-millennial climate and sea-level change” by Peter U. Clark et al, Nature Climate Change, April 2016 — Open copy. Excellent analysis of emission scenarios 0.5, 1, 1.5, and 2.0 times RCP8.5 for climate sensitivity of 3.5°C (shows bars for 1.5–4.5°C). But no mention of how we get those 21st C emissions, which means the discussion of how to prevent those emissions is ungrounded.
- “Northeastern North America as a potential refugium for boreal forests in a warming climate” by L. D’Orangeville et al, Science, 17 June 2016. This correctly describes RCP8.5 as a “high emissions scenario”. Progress!
- “Climate change, impacts and vulnerability in Europe 2016” by the European Environment Agency, 25 January 2017. As figure 1-6 shows, the report bases most of its climate forecasts on RCP8.5 (with some use of RCP4.5). It accurately describes the scenarios used.
- “Climate change is projected to have severe impacts on the frequency and intensity of peak electricity demand across the United States” by Maximilian Auffhammera, Patrick Baylisc, and Catherine H. Hausman, PNAS, 21 February 2017. Uses the “modest warming RCP4.5 scenario” and “the higher emissions scenario RCP8.5”.
- “A model integrating longshore and cross-shore processes for predicting long-term shoreline response to climate change” by Sean Vitousek et al, Journal of Geophysical Research – Earth Surface, April 2017. Uses RCP 4.5. Gated.
- “Impacts of climate change on European hydrology at 1.5, 2 and 3 degrees mean global warming above preindustrial level” by Chantal Donnelly et al in Climate Change, July 2017 — Uses RCP2.6, RCP4.5, and RCP 8.5.
- “Probabilistic climate change scenarios for viticultural potential in Québec” by Philippe Roy et al in Climate Change, July 2017 — RCPs 4.5 and 8.5 “have been adopted as lower and higher boundaries for uncertainty of the ’emissions’ type.”
- “Understanding extreme sea levels for broad-scale coastal impact and adaptation analysis” by T. Wahl et al in Nature Communications, 7 July 2017 — Uses only RCP4.5.
- Better, not good: “The impacts of rising temperatures on aircraft takeoff performance” by Ethan D. Coffel et al in Climate Change, September 2017. Uses both RCP4.5 and RCP8.5. Headline conclusions use RCP8.5.
- “Evolving understanding of Antarctic ice-sheet physics and ambiguity in probabilistic sea-level projections” by Robert E. Kopp et al. in Earth’s Future, 13 December 2017. Does not describe the scenarios. It runs the projections out to 2300, which is imo absurd. History shows that we cannot reliably estimate available tech in 2100, let alone 2300.
Visions of future doom for the public using RCP8.5
Similar misrepresentations are commonplace in articles for the public by scientists, journalists and activists, such as these…
- “The awful truth about climate change no one wants to admit” by David Roberts (writer) at VOX, 15 May 2015. He describes RCP8.5 as “The red line is the status quo — a projection of where emissions will go if no new substantial policy is passed to restrain greenhouse gas emissions.”
- “The scenario with the most warming is the ‘business-as-usual’ RCP8.5” — in an article at Climatica (“You & the experts exploring climate science”), 16 Dec 2013.
- “Surge In ‘Danger Days’ Just Around The Corner” by Brian Kahn at ClimateCentral, 12 August 2015 — They describe RCP8.5 as “assuming current greenhouse gas emissions trends continue unabated”, but don’t mention the other assumptions.
- “If nations continue emitting at current levels, most land areas on the planet will be more than 5°C hotter than now by 2100.” Said by Christopher Field, an ecologist at the Carnegie Institution for Science. He was co-chairman of WG2 of AR5, and is the U.S. nominee to lead the IPCC. (13 August 2015 interview.)
- “What Your Favorite Cities Will Look Like if We Do Nothing About Climate Change.Fancy a swim?” by Jack Holmes, Esquire, 10 Dec 2015. Based on RCP8.5 without mention of its assumptions.
- “The Price Tag of Being Young: Climate Change and Millennials’ Economic Future” at Demos, 22 August 2016. Based on RCP8.5; no mention of its assumptions.
- “This Melting Glacier in Antarctica Could Raise Sea Levels By 11 Feet” by Frennan Milliken in Motherboard, 17 December 2016. Based on this paper, which in turn is based on two papers using the worst-case RCP8.5 scenario, Milliken writes a scary article by omitting mention of the time required to melt that glacier (centuries or millennia) and the many qualifications the scientists give to their conclusions (they’re tentative due to lack of data).
- The Guardian typically goes full doomster to scare readers. They exaggerate a good study to create alarmist propaganda: “Climate change to cause humid heatwaves that will kill even healthy people” by not mentioning that the forecast using RCP8.5 is an unlikely worst case — or even that the study ran multiple scenarios.
It’s not too late to restart the debate
Every day we begin anew. The public policy debate about climate change can restart if we can get climate scientists to test the models from the first three Assessment Reports. The results from the past quarter-century will give us valuable data about their reliability, and perhaps break the current deadlock.
For More Information
Please like us on Facebook and follow us on Twitter. For more information see all posts about doomsters, about fear (perhaps become our greatest weakness), and especially about our odd affection for doomsters…
- Peak Oil Doomsters debunked, end of civilization called off.
- Spreading the news: the end is nigh! — A compendium of peak oil-related doomster predictions.
- Today’s conservative doomster warning (ludicrous but fun) — Paul Craig Roberts sees the End, published in the Leftist “Counterpunch”.
- Dreams of apocalypses show the brotherhood of America’s Left & Right.
- Collapsitarians and their doomster porn.
- Are 30 thousand species going extinct every year? — Spoiler: no.