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The UN's Devastating Climate Change Report Was Too Optimistic

The IPCC has been criticized for being "too alarmist. If anything, it is the opposite. With their latest report, they have been overly conservative."

A decade ago, the “father of global warming”—the first scientist to sound the alarm on climate change in the 1980s to the US Congress—announced that we were too late: the planet had already hit the danger zone.

In a landmark paper, James Hansen, then head of NASA’s Goddard Institute for Space Studies, along with seven other leading climate scientists, described how a global average temperature above 1°Celsius (C)—involving a level of carbon dioxide (CO2) in the atmosphere of around 450 parts per million (ppm)—would lead to “practically irreversible ice sheet and species loss.” But, they added, new data showed that even 1°C was too hot.


At the time the paper was issued in 2008, atmospheric concentrations of CO2 were around 385 ppm. This is “already in the dangerous zone,” explained Hansen and his colleagues, noting that most climate models excluded self-reinforcing amplifying feedbacks which would be triggered at this level—things like “ice sheet disintegration, vegetation migration, and GHG [greenhouse gas] release from soils, tundra, or ocean sediments.”

Such feedbacks constitute tipping points which, once triggered, can lead to irreversible or even runaway climate change processes.

According to Hansen and his co-authors, these feedbacks “may begin to come into play on time scales as short as centuries or less.” The only viable solution to guarantee a safe climate, they wrote, is to reduce the level of greenhouse gases to around 350 ppm, if not lower.

Today, we are well in breach of the 1°C upper limit. And we have breached this limit at a much lower level of atmospheric CO2 than Hansen thought would be necessary to warm this much—as of May 2018, the monthly average atmospheric CO2 had reached 410ppm (the August measurement puts it at 409ppm.) This is the highest level of CO2 the earth has seen in 800,000 years.

Ten years on from Hansen’s warning, the UN’s new climate report—presenting the consensus of the world’s leading climate scientists—informs us that if we continue at this rate, the planet will warm to around 1.5°C in just 12 years, triggering a sequence of increasingly catastrophic impacts.


According to a Met Office briefing evaluating the implications of the UN report, once we go past 1.5°C, we dramatically increase the risks of floods, droughts, and extreme weather that would impact hundreds of millions of people.

The IPCC says that this would just be the beginning: we are currently on track to hit 3-4°C by end of century, which would lead to a largely unlivable planet.


But there are fault-lines in the IPCC report. Among them is that its dire warning of coming catastrophe, though devastating, could well be conservative. A number of scientists point out that the report fails to fully acknowledge the role of amplifying feedbacks as highlighted by Hansen.

“Even with its description of the increasing impacts that lie ahead, the IPCC understates a key risk: that self-reinforcing feedback loops could push the climate system into chaos before we have time to tame our energy system, and the other sources of climate pollution,” Mario Molina, who shared the Nobel prize in chemistry in 1995 for his work on depletion of the ozone layer, told The Guardian.

In an essay for the Bulletin of the Atomic Scientists, Molina along with Veerabhadran Ramanathan, a professor of climate sciences at the University of California, San Diego, and Durwood J. Zaelke, president of the Institute for Governance & Sustainable Development in Washington DC, explain that climate change is not worsening in a simple, linear fashion, but rather by compounding and accelerating: “Adding 50 percent more warming to reach 1.5 degrees won’t simply increase impacts by the same percentage—bad as that would be. Instead, it risks setting up feedbacks that could fall like dangerous dominos, fundamentally destabilizing the planet.”


The IPCC “fails to adequately warn leaders” about six climate tipping points that work in this way. One of the more well-known such tipping points is Arctic sea ice, which could disappear in the summer in just 15 years, according to the Arctic Monitoring and Assessment Programme’s Snow, Water, Ice and Permafrost in the Arctic report. The ice acts as a reflector of heat back into the atmosphere, so the more it melts, the more the Arctic waters absorb heat.

This self-reinforcing feedback loop could lead to an ‘Arctic death spiral,’ where the loss of the sea ice accelerates the melting of permafrost, which some scientists believe could release large quantities of methane—a greenhouse gas 30 times more potent in driving warming than CO2—into the atmosphere.

Computer simulations of the Arctic’s thermokarst lakes—a certain type of Arctic lake that forms as permafrost thaws—are not incorporated into current global climate models.

The simulations suggest that toward mid or late century, “the permafrost-carbon feedback should be about equivalent to the second strongest anthropogenic source of greenhouse gases, which is land use change”, Katey Walter Anthony, an associate professor at the University of Alaska, Fairbanks, said in a press release announcing a NASA-funded study that found the “abrupt thawing” of permafrost could release large amounts of CO2 and methane via soil microbes “within a few decades.”


No wonder Professor Michael Mann, director of the Earth System Science Center at Penn State University and a former IPCC lead author, criticized deniers claiming the latest IPCC report is “too alarmist: If anything it is the opposite. Once again, with their latest report, they have been overly conservative (i.e. erring on the side of understating/underestimating the problem).”

The conservative nature of the IPCC is an inevitable result of thousands of scientists trying to generate a document that they all agree with. As a result, it tends to exclude scientific research around the uncertainties of when and how self-reinforcing feedbacks might cross tipping points leading to runaway effects.

One such paper published in August by the Proceedings of the National Academy of Science concludes that “even if the Paris Accord target of a 1.5°C to 2.0°C rise in temperature is met, we cannot exclude the risk that a cascade of feedbacks could push the Earth System irreversibly onto a ‘Hothouse Earth’ pathway.”

These shocking findings vindicate the early warnings of James Hansen and others, that a 1.5°C world would not just terraform the Earth beyond recognition, but might also trigger irreversible processes leading to a self-reinforcing cycle of warming that could ultimately culminate in an uninhabitable planet.

That worst-case outcome is not inevitable—but certain catastrophic outcomes are already locked in. According to a study in Climatic Change in 2016, parts of the Middle East and North Africa will become uninhabitable by 2050 due to intense summer heatwaves, even if we stay within 1.5°C.


The unliveable temperatures will likely spark mass migrations, which could exacerbate the danger of conflict. But as noted by Bob Ward, policy director at the the London School of Economics’ ESRC Centre for Climate Change Economics and Policy, the IPCC’s ‘summary for policymakers’ document (which condenses the full IPCC report for government officials) makes no mention of this.


Despite its blind spots, the IPCC throws down the gauntlet to global policymakers, demanding “rapid and far-reaching” transitions in land, energy, industry, buildings, transport, and cities to slash carbon emissions and begin drawing down carbon from the atmosphere.

By 2030, global CO2 emissions will need to drop 45 percent below 2010 levels—equivalent to over 60 percent below 2015 levels—reaching net zero by 2050. This will be a colossal undertaking. The UN report says it will require “unprecedented changes in all aspects of society.”

This will need to include a radical decrease in energy consumption, a rapid shift from fossil fuels to renewables, and fundamental transformations in lifestyles to bring down CO2 emissions. “Energy demand lower than present day, together with strong growth in economic output until the end of the century, is found in scenarios with shifts to more sustainable energy, material, and food consumption patterns,” the report says.

The radical transformation set out by the UN report is not a backward step, but a new pathway to a different kind of prosperity involving fundamental changes in core industries.


Construction needs to shift to greater resource efficiency, more use of insulation and the use of low carbon materials; transport should include more electric vehicles, a preference for walking or cycling for short distances, and government investment in sustainable mass transit options; energy requires more energy-efficient appliances, as well as widespread rooftop solar, solar water heaters, and more business and government support for renewables; food should involve reducing dairy and meat consumption, buying local and seasonal products as much as possible, and putting an end to food waste.


But other studies imply there is one glaring weakness in the IPCC report: its unbridled enthusiasm for geoengineering techniques to drawdown carbon from the atmosphere.

These play a major role in the report’s transition scenario pathways, and include ‘negative emissions’ technologies designed to drawdown carbon emissions from the atmosphere. The main technology being proposed is called ‘BECCS,’ which stands for ‘bioenergy with carbon capture and storage’. This basically proposes burning biomass for energy, and capturing the carbon emissions to be stored underground.

While the technology has been tested and proven at small-scales, commercial scale operations have yet to be built—and the key obstacle appears to be the massive costs associated with the technology.

"The goal of keeping warming under 1.5°C will require the virtual dissolution of the military-industrial complex"


A recent paper in the Royal Society of Chemistry’s Environment, Energy and Science journal examines BECCS from a ‘net energy’ standpoint to measure how much energy it would require, compared to what it produces. The paper found that under current technologies, “more energy is used to operate BECCS than what is returned to society”, a serious problem which could result in greater use of fossil fuels to keep BECCS alive, and “an increase in CO2 emissions, with a potential offset of the carbon dioxide removal service provided by BECCS.”

The study identifies ways BECCS might be made more efficient, cheaper, and less energy intensive, but admits that the practical feasibility of those mechanisms is unclear and “the scope for unintended consequences is vast.”

The last word on the subject came in last month via a comprehensive study published in Nature Communications, evaluating a whole gamut of negative emissions technologies. While acknowledging that “several techniques may eventually have the physical potential to contribute to limiting climate change,” the study concludes that “all are in early stages of development, involve substantial uncertainties and risks, and raise ethical and governance dilemmas.”

Reviewing a range of ‘climate dioxide removal’ and’ radiative forcing geoengineering’ technologies, the study finds that there is no certainty that any of them could ever scale: “Based on present knowledge, climate geoengineering techniques cannot be relied on to significantly contribute to meeting the Paris Agreement temperature goals.”


Even if they were actively pursued and worked on a global scale as hoped, “they would very unlikely be implementable prior to the second half of the century.” This would be far too late to avoid the IPCC’s safe upper limit of 1.5°C, and probably even 2°C.

The study’s conclusion is stark. We literally don’t have time to wait for geoengineering machines to do their magic: “Thus at present, the only reliable way to attain a high probability of achieving the Paris Agreement goals requires considerably increasing mitigation efforts beyond the current plans, including starting extensive emissions reductions much sooner than in the current NDCs [nationally determined contributions—emissions reduction pledges committed to by governments].”

In other words, relying on largely imaginary technologies to help us stave off the threat of extinction is astonishingly stupid. A more rational approach to ensuring that our children, and their children, have a viable future on planet Earth has to involve cutting emissions at source. And that requires a radically different economy.


The UN report does not go deep into detail on how the transition will require different economic priorities to what we’re accustomed to right now. But it does say that the transition “requires an evolution of global and national financial systems,” including “a potential redirection of 5 percent to 10 percent of the annual capital revenues.”


As meteorologist Eric Holthaus points out, this implies “the profit margin of basically every company.”

How can this be achieved? The report hints at the need for fundamental economic restructuring to change the way people and businesses are incentivized on a “day-to-day” basis.

The idea is to redirect capital investment away from short-term speculative ventures which are high-risk, high-debt and if profitable only of value to a tiny class of investors, into “long-term productive low-emission assets and services” of benefit to the wider public, as well as generating longer-term returns.

The financial and banking system will also need new regulation to mainstream this approach, along with new forms of “public-private partnerships” to support “new business models for small-scale enterprises and help households with limited access to capital.”

Without saying it aloud, these sorts of measures entail a fundamental shift in how capitalism as we know it operates, converting the economy from a structure dominated by narrow special interests which accumulate wealth for themselves, to one that serves communities.

Elsewhere, the report emphasizes a change in focus toward ways of improving quality of life for communities: “Community-led and bottom-up approaches offer potentials for climate-resilient development pathways at scale. At the level of individuals, communities, and groups, emphasis on well-being, social inclusion, equity, and human rights helps to overcome limitations in capacity.”


As Richard Heinberg, a senior fellow at the Post Carbon Institute, explains: “These sentences could easily have been written by an ecological economist or other post-growth theorist. Emphasis on well-being (instead of consumption) and equity (instead of growth) are mainstays of the eco-econ literature.”

But here, too, there are blind-spots.

The UN report demands radical change, but all encapsulated within a seemingly unquestionable assumption: that economic growth will and must continue. The report authors, says Heinberg, “don’t explicitly mention the possibility of ditching growth as a primary policy objective, presumably because government leaders might then be moved simply to dismiss the whole raft of recommendations.”


Of course, the idea that we can continue endlessly growing our economies while reducing our energy consumption, known as ‘decoupling’ in the technical literature, is attractive.

But it has been increasingly rejected in a number of recent studies, including one published earlier this year in Science of the Total Environment, in which economists find that the dependence of global economic growth on natural resources has not decreased, but increased by over 60 percent over the last century.

These grim findings fit with a study commissioned by the UN Secretary General’s Independent Scientific Group, who are drafting the UN’s Global Sustainable Development Report to be released next year.


That study, reported on by Motherboard in late August, warned that the global shift toward “energy sources that are less energy efficient” would undermine the basis of capitalist economies as they are currently structured. The study drew on the emerging field of ‘biophysical economics,’ which focuses on how economic activity depends on inputs of energy and materials.

Essentially, capitalism as we know it faces a triple whammy according to the study. Our fossil fuel addiction has led us into an increasing exploitation of dirtier, inefficient resources like unconventional oil and gas. Though available in abundance, they produce “less energy in generation than conventional oils.”

That increases the underlying costs of economic activity, as well as “sink costs” in the form of the cost of waste that our economic activity is generating. The biggest sink cost, of course, is climate change.

And finally, as we attempt to move away from fossil fuels towards renewables, we find that they still produce less energy than cheap conventional oil.

In short, “the era of cheap energy is coming to an end,” the paper concludes. This means that exponentially increasing economic growth is simply not going to be possible if it requires increasing energy and material inputs. As we shift to a low energy future, capitalism as we know it will need to fundamentally adapt.

These findings are not an outlier, but are widely corroborated by other studies. One recent study funded by the European Union’s Horizon 2020 program, published in February in the Elsevier Renewable Energy journal, calculated the available “net energy” that can be extracted from fossil fuels out to 2040.


The authors, a team of scientists from the Spanish National Research Council (the third largest public research institution in Europe), concluded that in a best-case scenario, global net energy from fossil fuels (the total amount of energy that can be extracted, minus the energy used to extract it) would peak around 2020-25, before gradually declining. This scenario sees global net energy in 2040 as being around the same value as it was three years ago—by this date global population is projected to grow from its current level of 7.3 billion people to about 9 billion.

The study acknowledges that ‘gross energy’—the total amount of energy being produced—will continue to rise out to 2040. But ‘net energy’—the energy available to society for different uses than simply producing more energy—will stagnate in coming decades. The worse case scenarios, considered more likely by the authors, see global net energy as having already peaked in 2015: “We see in this analysis that even in the most optimistic model… there is a reduction with respect to forecast in terms of the total World production of liquid hydrocarbon net energy, placing the projected growth of global total gross energy supply under serious stress.”

Unfortunately, even if the renewable energy transition kicks in to compensate for this, according to a paper in Nature Energy published in April, current transition scenarios see a 24–31 percent decline in available net energy by 2050. There is a way to make up for this, but it would require solar and wind power sources to “grow two to three times faster than in other proposals.”



Some argue that rather than attempting to stay on the economic growth treadmill, we need to accept the reality of running economies after growth.

Heinberg points out that if growth “currently comes from burning ever-growing quantities of fossil fuels in order to do economic work,” shifting to renewables inevitably requires an economic redesign that will impact economic activity.

As renewables are intermittent and produce electricity directly, to completely replace fossil fuels requires “a nearly complete transformation in how we use energy, and an extensive redesign of systems for generating, storing, and distributing energy.” Trying to maintain endless economic growth at the same time as replacing the very energy sources enabling that growth is like “redesigning and reconfiguring an airplane while it’s in flight.”

So Heinberg suggests that if we’re serious about avoiding climate catastrophe, we need to look at shrinking overall economic activity, de-emphasizing GDP in favour of “quality of life indicators”, and reigning in population growth while instituting a guaranteed jobs program or a universal basic income.

“We’re headed for a crash sooner or later,” he observes. “Wouldn’t it be better to make the post-growth transition on our terms, rather than in crisis mode? Why not use the inevitability of the end of growth to our advantage by planning to reduce both mindless consumerism and carbon emissions, while increasing equity and quality of life?”

Others are not convinced that a low energy future is inevitable. A new book published in August, The Earth is Not for Sale, by David and Peter Schwartzman, a father-son environmental science duo (the former a professor emeritus at the Department of Biology, Howard University; the latter teaching environmental studies at Knox College), argues the opposite.

An increase in net energy from renewable energy sources is entirely feasible if done right, they conclude—and could sustain high levels of prosperity worldwide with a fundamentally egalitarian economic system.

The main prerequisite for this pathway, though, is the elimination of carbon emissions from the US military—widely considered to be the biggest institutional consumer of crude oil in the world.

“If the goal of keeping warming under 1.5°C is achieved, which will require the virtual dissolution of the military-industrial complex, then a rapid transition to wind and solar power in a high, not low [net energy] future, is possible,” David Schwartzman told me. This could lead to “higher, not lower global energy use, especially for the global South, wiping out energy poverty and generating the capacity for climate adaptation and mitigation.”

Wherever we stand on the prospects for economic growth, the upshot is that economics for a future after fossil fuels has to be less concerned with exponentially increasing how much we materially produce and consume, as opposed to how well we actually deliver quality of life.

This is the sort of ground-breaking economic program touted by the UK’s Green New Deal Group, a network of British economic thinkers, energy experts and politicians established after the 2008 financial crash.

Last month, the Group—which includes economist Ann Pettifor, a government advisor and director of Policy Research in Macroeconomics; The Guardian’s economics editor Larry Elliott; Green Party MP Caroline Lucas, also Vice Chair of the All Party Parliamentary Group on Peak Oil and Gas; and Jeremy Leggett, chairman of British solar energy firm Solarcentury—issued a new policy brief warning of the risk of another financial crash due to a rising debt-bubble.

Instead of bailing out banks with trillions of dollars of taxpayers’ money, as happened in the last crisis, the Group recommend productive investment in a grand infrastructure revival that would decrease energy use, institutionalize ‘circular economy’ recycling principles across industries, build the next generation of renewable energy infrastructure, establish a new clean public transport system, and create millions of jobs.

“The Green New Deal is deliverable,” concludes the brief. “What is required is the political will to deliver it.”

The UN report offers a wake-up call on the urgency of taking action. At stake is the prosperity—and survival—of generations to come. And there’s no time to lose. So if politicians aren’t paying attention, it’s up to citizens to make their voices heard louder than ever.