Scientific Understatement

In the previous blog we looked at the disappointing and inadequate response of political leaders to the imminent global crisis of climate change. Some of this can be put down to the nature of the IPCC itself and the tenor of its reports. The IPCC was established by the United Nations to assess the global consensus on climate science as a basis for policymaking. During its existence, the IPCC has performed indispensable work of the highest scientific standard in pulling together a periodic consensus of the most exhaustive scientific investigation in world history. IPCC Assessment Reports are compiled by working groups of scientists within guidelines that urge the building of consensus conclusions from evidence presented, though that evidence itself may be diverse and sometimes contradictory in nature. This model tends to produce bland and conservative conclusions which are further watered down by the political representatives of the 195 member nations of the IPCC.

While the full-length IPCC  Assessment Reports are compiled by scientists, the shorter and more widely reported Summaries for Policy Makers require consensus from diplomats in ‘a painstaking, line-by-line revision by representatives from more than 100 world governments — all of whom must approve the final summary document’.

As early as the IPCC’s first report in 1990, the United States, Saudi Arabian and Russian delegations acted in ‘watering down the sense of the alarm in the wording, beefing up the aura of uncertainty’.

In 2014, TheGuardian reported increasing evidence that “the policy summaries on climate impacts and mitigation by the IPCC were significantly ‘diluted’ under political pressure from some of the world’s biggest greenhouse gas emitters, including Saudi Arabia, China, Brazil and the United States”.

In the face of this political interference, some of the participants have ‘broken cover’ to reveal what scientists, decision-makers and other stakeholders have been saying, often behind closed doors, about the culture of failure and scientific reticence in which climate policy-making has become embedded. In August 2018, David Spratt and Ian Dunlop of the Breakthrough National Centre for Climate Restoration released the influential report What Lies Beneath, which argues that existential risk of climate change has been understated. Spratt and Dunlop state that:

‘Climate change is now an existential risk to humanity. That is, a risk posing large negative consequences which will be irreversible, resulting in major reductions in global and national populations, mass species extinction, economic disruption, and social chaos unless carbon emissions are reduced far more rapidly than proposed under the Paris agreement.

 It is no longer possible to follow a gradual transition path to restore a safe climate. We have left it too late; emergency action, akin to a war footing, will eventually be accepted as inevitable. The longer that takes, the greater the damage inflicted upon humanity.’

Partially in response to this, on 31 October 2018, a new group, Extinction Rebellion, was launched in the UK pledging to commit repeated acts of disruptive, non-violent civil disobedience in the face of political inaction.  To explain their philosophy, they produced the following declaration:

Political Science?

In the last blog we looked at the recent joint statement from scientist signatories to the IPCC’s Special Report on Global Warming of 1.5 °C  which stressed that, in order to limit the average temperature rise to 1.5°C, the best immediate solution requires protecting and sustainably managing the forests we have and restoring the forests we’ve lost.

Fortunately, it’s now possible to quantify just how much of the forest cover, which was once abundant across the globe, we’ve already destroyed. A study by researchers from the University of Queensland and the Wildlife Conservation Society, published in the journal Nature on 31 October 2018 shows that just five countries hold 70% of the world’s remaining untouched wilderness areas, and urgent international action is needed to protect them.

The five nations are Australia, the US, Brazil, Russia and Canada. The researchers have produced a global map that illustrates which countries are responsible for nature that is still devoid of heavy industrial activity.

Unfortunately, at least two of the countries in the top five have political leaders who are not just indifferent to the sort of radical changes that need to be taken to limit the extent of global rises in temperature, they are positively hostile to them.

In Brazil, Jair Bolsonaro was elected as president on 28 October 2018 with 55% of the popular vote.

This is terrible news for those who wish to see the conservation of the precious Amazon rainforest. Bolsanaro was elected following strong backing by Brazil’s influential agribusiness and mining lobbies, who want to open up the Amazon, Cerrado and other protected areas. If the Amazon deforestation rate – already running at a rate of 52,000 square kilometres per year – accelerates, the global implications could be immense.

President of the US, Donald Trump, is also a block to the prospect of genuine meaningful change. In comments, made during an interview with CBS’s 60 Minutes on 14 October 2018, less than a week after the publication of the IPCC’s Special Report on Global Warming of 1.5 °C, he stated:

‘We have scientists that disagree with [human-caused global warming] … You’d have to show me the [mainstream] scientists because they have a very big political agenda’

His comments demonstrate that he is unaware of the IPCC’s work and the 97% expert consensus that exists on human-caused global warming. As Nasa atmospheric scientist Kate Marvel recently put it:

‘We are more sure that greenhouse gas is causing climate change than we are that smoking causes cancer.’

In the same interview Trump went on to say of climate change:

‘But I don’t know that it’s manmade. I will say this. I don’t want to give trillions and trillions of dollars. I don’t want to lose millions and millions of jobs. I don’t want to be put at a disadvantage.’

He then added that temperatures ‘could very well go back’ – although he did go on to elaborate how he imagined this might happen. It appears that, just as the world desperately requires a concerted political effort to make a real change, the politicians are not up to the task.

 

The Future of Our Forests

Because governments have left it so late, it’s difficult to see how we can stop more than 1.5C of global warming without finding ways of removing CO2 from the atmosphere. Currently, the only way of doing it that has been demonstrated at scale is to allow trees to return to deforested land. A joint statement from scientist signatories to the IPCC’s Special Report on Global Warming of 1.5 °C  makes the point that limiting the average temperature rise to 1.5°C requires both drastic reduction of CO2 emissions and removing excess carbon dioxide from the atmosphere.  While high-tech CO2 solutions are under development, the natural technology of forests is our only proven option of meaningfully achieving carbon balance.

The scientists have highlighted five reasons why limiting global warming requires protecting and sustainably managing the forests we have, and restoring the forests we’ve lost. These are:

1. The world’s forests contain more carbon than exploitable oil, gas, and coal deposits, hence avoiding forest carbon emissions is just as urgent as halting fossil fuel use.
2. Forests currently remove around a quarter of the CO2 humans add to the atmosphere, keeping climate change from getting even worse.
3. Achieving the 1.5°C goal also requires massive forest restoration to remove excess carbon dioxide from the atmosphere. Reforestation and improving forest management together have large potential to remove CO2 from the atmosphere. These “natural climate solutions” could provide 18% of cost-effective mitigation through 2030.
4. Bioenergy is not the primary solution. In some areas, such as high carbon tropical forests and peatlands—both of which continuously remove carbon from the atmosphere—conservation is the best option.
5. Tropical forests cool the air around them and the entire planet, as well as creating the rainfall essential for growing food in their regions and beyond.

 

In responding to the IPCC report, the message from the scientists is simple:

“Our planet’s future climate is inextricably tied to the future of its forests.”

 

Geoengineering Solutions?

The authors of the IPCC’s Special Report on Global Warming of 1.5 °C  (SR15) published on 8 October 2018 have acknowledged that the world may increasingly look to geoengineering solutions which they says could be adopted as a temporary ‘remedial measure’ if the world heads towards dangerous levels of warming.

In light of the study published in the journal Nature on 31 October 2018, which showed that the IPCC’s timeframe was based on possibly conservative estimates of global warming, there are several possible solutions being considered.  These include; stratospheric aerosol injection, ocean fertilisation, CO2 removal, marine cloud brightening, cirrus cloud thinning and ground-based albedo modification.

Although the IPCC report does not include such strategies in their pathways to 1.5°C above pre-industrial temperatures, it raises the possibility that it could be used as a supplementary measure if this target is missed. The report states:

‘If mitigation efforts do not keep global mean temperature below 1.5C, solar radiation modification can potentially reduce the climate impacts of a temporary temperature overshoot, in particular extreme temperatures, rate of sea level rise and intensity of tropical cyclones, alongside intense mitigation and adaptation efforts.’

A search for geoengineering solutions looks increasingly likely as the world is almost certain to miss the 1.5°C goal. Current national pledges are forecast to lead to at least 3°C of warming by the end of the century – and that is if governments keep their commitments. However, there are major uncertainties about the effectiveness and the environmental and ecological impacts of the solutions themselves, which mean we would be far better off if policymakers strengthened natural cooling systems such as forest cover and accelerated efforts to reduce carbon emissions.

Ocean Warming Underestimated!

The IPCC’s Special Report on Global Warming of 1.5 °C  (SR15) published on 8 October 2018 warned that humanity must cut carbon emissions in half by 2030 in order to avert climate catastrophe by 2040. It now appears that this timeframe was based on possibly conservative estimates of global warming.

A study published in the journal Nature on 31 October 2018 by a team led by Professor Laure Resplandy of Princeton University shows that Earth’s oceans have retained 60 percent more heat each year over the past 25 years than scientists previously believed. The result of this study—which relies on high-precision oxygen measurements dating back to 1991—suggests that ocean warming is at the high end of previous estimates, with implications for policy-relevant measurements of the Earth’s response to climate change, such as the IPCC’s recent report. The implication is that we have even less time than we thought to reduce CO2 emissions to zero and keep the global temperature rise within the 1.5°C target.

1.5°C – the clock is ticking

The Special Report on Global Warming of 1.5 °C  (SR15) was published by the IPCC on 8 October 2018.  The report was called for by the UNCCC in order to ‘deliver the authoritative, scientific guide for governments’ to deal with climate change.

Its key finding is that meeting a 1.5 °C target is possible but would require ‘deep emissions reductions’ and ‘rapid, far-reaching and unprecedented changes in all aspects of society.’

 The report finds that that ‘limiting global warming to 1.5 °C compared with 2 °C would reduce challenging impacts on ecosystems, human health and well-being’ and that a 2°C temperature increase would exasperate extreme weather, rising sea levels and diminishing Arctic sea ice, coral bleaching, and loss of ecosystems, among other impacts.  SR15 also has modelling that shows that ‘Global net human-caused emissions of carbon dioxide (CO2) would need to fall by about 45 percent from 2010 levels by 2030, reaching ‘net zero’ around 2050.’

 

That gives us 12 years to reduce our CO2 emissions by half and 32 years to reduce them totally.

 

Although the report stresses that urgent and unprecedented changes are needed to reach these targets, they also state that they are still affordable and feasible.

Debra Roberts, a co-chair of the IPCC working group on impacts, said:

‘This is the largest clarion bell from the science community and I hope it mobilises people and dents the mood of complacency. It’s a line in the sand and what it says to our species is that this is the moment and we must act now,’

The report urges radical change now to ensure that the temperature rise due to man-made climate change stays between 1.5°C and 2°C. The IPCC were absolutely clear that climate change is already happening and upgraded its risk warning from previous reports. It went on to warn that every fraction of additional warming would worsen the impact.

The IPCC’s international community of scientists reviewed 6,000 studies in preparing the report.  In doing so they realised that the global change caused by just half a degree rise in temperature was substantial. At 1.5°C the proportion of the global population exposed to water stress could be 50% lower than at 2°C. Food scarcity would be less of a problem and hundreds of millions fewer people, particularly in poor countries, would be at risk of climate-related poverty. The half a degree rise also makes a huge difference to the natural world. Plants and insects, which are vital for the pollination of crops, are almost twice as likely to lose half their habitat at 2°C compared with 1.5°C. Corals would be 99% lost at the higher of the two temperatures, but more than 10% have a chance of surviving if the lower target is reached.

The report will be presented to governments at Katowice Climate Change Conference of the Parties (COP 24) to be held in Poland in December 2018. At the current level of commitments, the world is on course for a disastrous 3°C of warming. Meanwhile, the UK is pushing ahead with gas fracking, Norway with oil exploration in the Arctic, and the German government wants to tear down the ancient Hambach forest to dig for coal.

Professor James Hansen – director of the Program on Climate Science, Awareness and Solutions at the Earth Institute at Columbia University – has said of the difference between 1.5°C and 2°C that:

‘1.5°C gives young people and the next generation a fighting chance of getting back to the Holocene or close to it.’

How Did We Get Here?

In November 1989 the World Meteorological Organization WMO and UN Environment Programme UNEP established the Intergovernmental Panel on Climate Change IPCC.  The IPCC is the internationally accepted authority on climate change and is composed of thousands of scientists and other experts who contribute on a voluntary basis.  The role of the IPCC is to provide the world with an objective, scientific view of climate change and its political and economic impacts.  The IPCC reports have the agreement of climate scientists globally and the consensus of more than 120 participating governments.

The IPCC has published five comprehensive assessment reports reviewing the latest climate science, as well as a number of special reports on particular topics.

The IPCC published its First Assessment Report (FAR) in 1990, a supplementary report in 1992, a Second Assessment Report (SAR) in 1995, a Third Assessment Report (TAR) in 2001, a Fourth Assessment Report (AR4) in 2007 and a Fifth Assessment Report (AR5) in 2014.

In November 1990 The IPCC’s first assessment report stated that ‘emissions resulting from human activities are substantially increasing the atmospheric concentrations of the greenhouse gases: CO₂, methane, CFCs and nitrous oxide. These increases will enhance the greenhouse effect, resulting on average in an additional warming of the Earth’s surface.

The 1992 supplementary report was an update, requested following the UNFCCC (United Nations Framework Convention on Climate Change)  Earth Summit in Rio de Janeiro in June of that year. The IPCC concluded that research since 1990 did “not affect our fundamental understanding of the science of the greenhouse effect and either confirm or do not justify alteration of the major conclusions of the first IPCC scientific assessment”.

The 1995 IPCC report estimated that a doubling of CO2, which was expected to come around the middle of the 21st century, would raise the average global temperature somewhere between 1.5 and 4.5°C. That was exactly the range of numbers announced by important groups one after another ever since 1979, when a committee of the U.S. National Academy of Sciences had published 3°C plus or minus 1.5°C as a plausible guess.

The third report of the IPCC, issued in 2001, bluntly concluded that the world was rapidly getting warmer. Further, strong new evidence showed that ‘most of the observed warming over the last 50 years is likely to have been due to the increase in greenhouse gas concentrations.’ Computer modelling had improved to the point where the panel could confidently state that the rate of warming was ‘very likely to be without precedent during at least the last 10,000 years.’ Further, the range of warming that the IPCC predicted for the late 21st century now ran from 1.4°C up to 5.8°C. China’s rapid industrialisation had led to an upward revision of predictions and this range was not for the traditional doubled CO2 level, which was now expected to arrive around mid-century, but for the still higher levels that would come after 2070 unless the world took action.

In February 2005, the Kyoto Protocol came into effect with 141 signatory nations, including all the major industrial nations except the US.  The protocol established legally binding obligations for developed countries to reduce their greenhouse gas emissions in the period 2008–2012.

The Fourth IPCC report published in 2007 saw most of the world’s climate scientists contributing to shaping its conclusions. Computer modellers worked to produce more accurate global warming results specifically for the report. The range of temperatures predicted for the end of the century had not changed much since the 2001 report. Their best guess was still roughly 3°C of warming, but they had grown more certain that we were very unlikely to get away with a rise of less than 1.5°C. The computer models did not agree so well on the upper limit — there was a small possibility that global temperature could soar to 6°C or even higher. That possibility increased if, contrary to the IPCC’s baseline assumption, the world continued with business-as-usual instead of severely restraining its emissions.

The 2010 United Nations Climate Change Conference in Cancún, Mexico, recognised that ‘climate change represents an urgent and potentially irreversible threat to human societies and the planet, which needs to be urgently addressed by all parties’. It produced an agreement that deep cuts in global greenhouse gas emissions were required to hold the increase in global average temperature below 2°C above pre-industrial levels (computer studies tended to show that serious effects for life on earth would begin to appear above 1.5°C). The agreement also notes that addressing climate change requires a paradigm shift towards building a low-carbon society.

On May 9, 2013, atmospheric CO₂ levels surpassed 400 ppm (parts per million) for the first time in recorded history. This recent relentless rise in CO₂ shows a remarkably constant relationship with fossil-fuel burning.

The Fifth IPCC Assessment Report was finalised in 2014. The principal findings were:

• Warming of the atmosphere and ocean system is unequivocal. Many of the associated impacts such as sea level change (among other metrics) have occurred since 1950 at rates unprecedented in the historical record.
• There is a clear human influence on the climate

It also projected that:

• Further warming will continue if emissions of greenhouse gases continue.
• The global surface temperature increase by the end of the 21st century is likely to exceed 1.5 °C relative to the 1850 to 1900 period for most scenarios, and is likely to exceed 2.0 °C for many scenarios

 

Global emissions of greenhouses gases, however, continued to increase. In 2014, the 400 ppm mark of CO2 in the atmosphere was passed in March. The average CO2 concentrations for March, April and June 2014 were all above 400 ppm, the first time that has been recorded. This is a large increase from pre-industrial CO2 concentrations, which were around 280 ppm. These high CO2 levels have not been seen on Earth in somewhere between 800,000 and 15 million years . If fossil-fuel burning continues at a business-as-usual rate – such that humanity exhausts the current oil, gas and coal reserves over the next few centuries – CO₂ will continue to rise to levels of order of 1500 ppm. The atmosphere would then not return to pre-industrial levels even tens of thousands of years into the future.

In 2015 The Scripps Institution of Oceanography recorded atmospheric CO2 levels of above 400 ppm on the first day of the year, followed by January 03 and January 07. The levels of global greenhouse gas emissions continue to rise as do global temperatures (see graphs below).

The sixth IPCC report is due in 2022.

 The IPCC Special Report on Global Warming of 1.5 °C was published on 8 October 2018.