Draws together current climate research from around the world to help inform and guide the stark choices that now stand before us. —–
No 2694 Posted by fw, December 25, 2020 —
“Climate Reality Check 2020 draws together current climate science research to present 20 critical understandings, observations and insights to help inform and guide the stark choices that now stand before us. It is a resource designed to help climate practitioners, advocates, journalists, business leaders, [citizens] and policymakers better understand and address the alarming mismatch between the current climate risks and considerably inadequate level of climate action. The underestimation of the seriousness of the climate reality today poses grave consequences for the safety, health and well-being of our societies, the capacity of governments to protect the people, and regional and global stability.” —Breakthrough – National Centre for Climate Restoration
The Breakthrough – National Centre for Climate Restoration is an independent think-tank established in 2014, located in Melbourne, Australia. Their website describes Breakthrough’s mission as the development and promotion of strategies, innovation and analysis which are required to restore the climate to a safe condition.
Below is my repost of Breakthrough Australia’s 60-page climate reality checklist report. The content is organized under four headings: CURRENT IMPACTS – Analysis & assessment of threats; MAJOR RISKS – Understanding the urgency; CRITICAL ACTIONS – Key response for protection; and SUMMARY – Overview and key points. Sixty-one footnotes, are included at the bottom of the post; in the text of the report, footnotes appear inside square brackets [ ]
To download the original, 60-page PDF report, click on the following linked title.
Climate Reality Check 2020 draws together current climate research from around the world to present 20 critical observations, insights and understandings to help inform and guide the stark choices that now stand before us.
IMPACTS & RISKS – Analysis & assessment of threats
If we continue down the present path there is a very big risk that we will just end our civilization. The human species will survive somehow but we will destroy almost everything we have built up over the last two thousand years. – Prof. Hans Joachim Schellnhuber, Director emeritus of the Potsdam Institute
CURRENT IMPACTS — Analysis & assessment of threats
1/ Warming is approaching 1.2°C and accelerating — The rate of global temperature increase is speeding up
+ The 5-year global average temperature for 2015-2019 was 1.16°C above a late 19th-century baseline. 
+ Two of the last four years have been ≥ 1.2°C.
+ Hotter years are usually associated with El Nino conditions. It is ominous that 2020 could be ~1.2°C during La Nina conditions.
+ Warming has accelerated to ~0.25°C for the most recent 2010-19 decade.  Average decadal rate of warming prior to 2010 was ≤ 0.2°C.
+ The next 25 years are projected to warm at a rate of 0.25–0.35°C per decade. 
2/ 1.5°C warming is likely by 2030, even earlier — Breaching 1.5°C Paris Agreement boundary likely a decade ahead of IPCC projections
+ Many research papers project warming to reach 1.5°C around 2030, or sooner. 
+ A comparison of results from the latest generation of climate models suggest 1.5°C may be only five-to-seven years away (see Table 2). 
+ Reaching 1.5°C by 2030 would be a decade ahead of IPCC projections. 
+ Rising emissions, declining aerosols (air pollution) and natural climate cycles will contribute to faster warming,  as will greater stratification of the ocean with a hotter layer of water on top contributing to faster warming. 
3/ Reducing emissions alone will have no significant impact on warming trend over next two decades — As fossil fuel use declines, so will aerosol emissions, which have been offsetting some warming
+ A by-product of burning fossil fuels are sulfate aerosols, which have a strong cooling impact, but are short-lived in the atmosphere. Aerosols have been “masking” some of the warming so far. 
+ Declining coal use and clean air policies reduce the aerosol impact. This is our “Faustian bargain”:  as fossil fuel use declines so does the aerosol cooling, so that for the next two decades lower emissions will have little impact on the warming trend.
+ A 5% annual reduction in emissions of a single greenhouse gas, from 2020 and based on a middle- road emissions path, has no statistically significant effect on warming for more than two decades, as compared to a no- mitigation pathway (see Table 1). 
+ Nevertheless, fast emission cuts are vital to flatten the warming curve.
4/ 1.75–2.4°C of warming for current greenhouse gas levels — Higher temperatures will result from greenhouse gases already in the atmosphere
+ Earth energy imbalance (EEI) is the radiative imbalance at the top of the atmosphere (between outgoing and incoming radiation), which is driving global warming.
+ The current EEI is 0.6–0.75°C.  Added to the 1.15–1.2°C of warming so far, expected warming is 1.75–1.95°C for the current level of greenhouse gases.
+ The total theoretical warming, if the current level of greenhouse gases (~490 ppm CO2e)  were maintained, is ~2.4°C at equilibrium. 
+ If a prudent risk-management approach is taken — with attention given to the high- damage, high-end possibilities rather than middle-of-the- road probabilities — there is no carbon budget for the 2°C target. 
5/ On current emissions path, 2°C warming well before 2050 — Upper Paris boundary of 2°C likely to be breached before mid-century
+ A comparison of current climate model projections show the median year in which warming thresholds of 1.5°C, 2°C, 3°C, 4°C and 5°C are reached for three emissions trajectories: low, central and high (see Table 2).  Using the MAGIC model, timings of key temperatures of 1.5°C, 2°C, 2.5°C and 3°C are illustrated with dots for various emission paths (see Chart 3 overleaf).  [Warming so far is consistent with the RCP8.5 high-emissions path.]
+ The emissions path has little impact on timing of the 1.5°C threshold.
+ 2°C will be reached before 2050 for both the high and central emission scenarios.
+ Under a high emissions scenario, 3°C may be reached ~2060 and 5°C before 2100.
The climate emergency is evolving faster than predicted. We must accelerate our response, with ambition and urgency. This is the battle for our lives. — António Guterres, Un Secretary General
6/ The picture painted by the IPCC is too conservative — There is a serious underestimation of future climate impacts
+ Until now, climate models used for projecting future warming and calculating carbon budgets in IPCC reports estimate a warming sensitivity of ~3°C (for doubled CO2).
+ Including factors such as “slow” feedbacks (carbon stores, such as permafrost) and albedo changes (reflectivity), warming may be as high as 5–6°C for a doubling of CO2 for a range of climate states between glacial conditions and ice-free Antarctica. 
+ Future warming is likely to be 15% higher (~0.5°C) for high scenarios by 2100 compared to raw climate model projections reported so far by the IPCC. 
+ Climate models do not account well for increased warming due to loss of Arctic sea-ice: “Losing the reflective power of Arctic sea ice will advance the 2ºC threshold by 25 years.” 
7/ 1.5°C is not a safe target — Vital ecosystems including The Great Barrier Reef are facing devastation now
+ The Great Barrier Reef is in a death spiral: at the current level of global warming, it will bleach on average once every three-to-four years,  whereas recovery takes a decade or more.
+ West Antarctic Ice Sheet (WAIS) glaciers have passed a tipping point.  The Paris Agreement temperature target of 1.5°C is sufficient to drive runaway retreat of WAIS. 
+ Parts of East Antarctica might be similarly unstable. 
+ Three-quarters by volume of summer Arctic sea-ice has already been lost. 
+ One-quarter of the Himalayan & Tien Shan ice sheets have already been lost. 
+ The forest systems are oscillating to non-forest ecosystems in eastern, southern & central Amazonia. 
8/ 2°C is very dangerous — With further tipping points close at hand, 2°C is a recipe for disaster
+ Further tipping points could be triggered at low levels of global warming. A cluster of abrupt shifts could occur between 1.5°C and 2°C (#10). 
+ These include the Greenland Ice Sheet, which is close to a tipping point,  previously estimated to be around 1.6°C;  and the Amazon rainforest. 
+ It is a big mistake to think we can “park” the Earth System at any given temperature rise – say 2°C – and expect it to stay there.  2°C may not be a point of system stability.
+ Former NASA climate chief Prof. James Hansen said that it is “well understood by the scientific community” that goals to limit human-made warming to 2°C are “prescriptions for disaster”. 
9/ The world is on a 3-5°C warming path by 2100 — We are heading for levels of warming incompatible with an organized global community
+ Global temperatures are on track for 3–5°C of warming by 2100. 
+ The temperature increase is still on the high-emissions RCP8.5 path, and RCP8.5 is also the best match to mid-century under current and stated policies. 
+ Prof. Kevin Anderson says that “a 4°C future is incompatible with an organised global community, is likely to be beyond ‘adaptation’, is devastating to the majority of ecosystems and has a high probability of not being stable”. 
+ Prof. Johan Rockström says that at 4°C: “It’s difficult to see how we could accommodate eight billion people or maybe even half of that.” 
10/ 2°C may trigger a “Hothouse Earth” scenario of self-reinforcing warming — We are perilously close to dramatic climate change that could run out of our control
+ The “Hothouse Earth” scenario is one in which climate system feedbacks and their mutual interaction drive the Earth System climate to a point of no return, whereby further warming would become self-sustaining (that is, without further human perturbations). 
+ This planetary threshold could exist at a temperature rise as low as 2°C, possibly even in the 1.5°C–2°C range. 
+ Similarly, Prof. James Hansen warned in 2007 that: “Recent greenhouse gas emissions place the Earth perilously close to dramatic climate change that could run out of our control.” 
+ The paper Trajectories of the Earth System in the Anthropocene (known as “Hothouse Earth” paper) was ranked as the most impactful climate research article of the year in 2018. 
11/ 3°C of warming would be catastrophic — Sea levels will eventually rise tens of metres for current level of greenhouse gases
+ At 3°C of warming, food production would be inadequate to feed the population due to a global average one-fifth decline in crop yields, a decline in nutrition content of crops, catastrophic decline in insect populations, desertification, monsoon failure and chronic water shortages. 
+ 3°C would be “catastrophic” for the livelihoods of the world’s poorest three billion people, comprising mostly subsistence farmers, whose livelihood will be severely impacted, if not destroyed, with a one- to five-year megadrought, heat waves, or heavy floods. 
+ Sea levels would eventually rise by tens of metres: “Even if we curb all CO2 emissions today, and stabilize at the modern level, then our natural relationship suggests that sea level would continue to rise to about 25 metres.” 
12/ Climate history previews our hot future — The last time Earth had the current level of greenhouse gases, there were forests in Antarctica
+ During the Pliocene, 3–5 million years ago, when the CO2 level was similar to today, temperatures were 2–4°C higher than pre-industrial and sea levels 20–25 metres higher. 
+ “The indication is that there [was] no Greenland ice sheet any more, no West Antarctic ice sheet and big chunks of East Antarctic [ice sheet] taken.” 
+ During the Pliocene, there were trees at the South Pole. “I call them the last forests of Antarctica. They were growing at 400 ppm CO2, so this may be where we are going back to with ice sheets melting at times, which may allow plants to colonize again,” says Jane Francis, the Executive Director of the British Antarctic Survey. 
MAJOR RISKS – Understanding the urgency
Crisis prevention requires strategic coordination at the system level… Because of the non-linearity of the corona pandemic and climate change, the creation of capacities for adaptation to these crises does not suffice. Only if the unmanageable is avoided is there a chance to stabilize the system. — Kira Vinke, Sabine Gabrysch, Emanuela Paoletti, Johan Rockström And Hans Joachim Schellnhuber, Corona & The Climate: A Comparison Of Two Emergencies
13/ The risks are existential — We are in a state of planetary emergency: the risk and urgency are acute
+ In 2019 scientists offered an emergency formula.  Generally, risk is considered to be the potential damage multiplied by the probability, but in this equation, another element is added, called urgency. This is the relationship between: the reaction time “ ” (how long it takes to solve a problem); and the intervention time “T” (the time you actually have, before it is “too late”).
+ Think of the Titanic: “If reaction time is longer than the intervention time left ( / T > 1), we have lost control.” 
+ “The evidence from tipping points alone suggests that we are in a state of planetary emergency: both the risk and urgency of the situation are acute… If damaging tipping cascades can occur and a global tipping point cannot be ruled out, then this is an existential threat to civilization.” 
14/ The risks are existential for nature, too — We are now entering the sixth mass extinction in Earth’s history
+ The rate of change matters. Many ecosystems (e.g. Arctic, corals, dry subtropics) have not adapted to 1°C change in a century (0.1°C/decade).
+ Warming for the 2010-2019 decade was >0.25°C, and projected to be higher in next 2–3 decades (#2)
+ We are now entering the sixth mass extinction in Earth’s history.
+ At warming of 3.5°C by 2100 (rate of 0.3°C/decade), only 30% of all impacted ecosystems can adapt and only 17% of all impacted forests can adapt.  Common tree species cannot adapt naturally by poleward shifts to >2°C per century.
+ The “burning embers” diagram from the IPCC special report SR15 shows “very high risk” with limited ability for unique and threatened ecosystems to adapt to 2°C of warming (Chart 6).
15/ Sensible risk-management requires special attention be given to high-end possibilities –– Precautionary action is necessary to prevent existential outcomes
+ An emergency exists if the world is approaching a global cascade of tipping points that leads to a “hothouse” climate state: “Cascading effects might be common… examples are starting to be observed.” 
+ Climate change is an existential risk to human civilization (contemporary society). 
+ This requires special precautions beyond conventional risk management practice if the increased likelihood of “fat tail” (high end) risks are to be adequately dealt with.
+ The “burning embers” diagram from the IPCC special report SR15 shows “very high risk” with limited ability for unique and threatened ecosystems to adapt to 2°C of warming (Chart 6).
CRITICAL ACTIONS – Key response for protection
+ It is already too hot (#6), and we are dangerously close to the “Hothouse Earth” scenario (#10), yet current greenhouse gas levels may be enough to cause 2–4°C of warming in the longer term (#12).
+ The primary task is to build capacity for emergency speed and scale emissions elimination, and to minimize the rate and magnitude of warming.
+ Mobilizing for zero emissions by 2030 is critical.
+ A 2050 timeframe will not prevent catastrophic outcomes.
+ Long-term targets are an excuse for procrastination. That has been the history of international climate policy-making.
17/ The Earth is already too hot: large-scale carbon drawdown is vital — Removing carbon dioxide from the atmosphere can cool an overheated Earth
+ Stabilization (at current climate) would require carbon drawdown of 60 ppm (back to ~350 ppm) to stop further warming of ~0.7°C. Lowering current warming would require more drawdown [.57]
+ CO2 may be drawn out of the atmosphere by natural cycles on land (by reforestation, for example) and in oceans, by rock weathering and by storage in soils. 
+ These processes can be enhanced, and new technologies are being developed. Large-scale research and deployment is crucial.
+ Drawdown is a slow process that will not provide active cooling until it is greater than level of emissions.
+ We should be wary of relying on claims that in the distant future bioenergy with carbon capture and storage (BECCS) is a panacea. 
18/ A safe means of immediate cooling is critical to protect people & nature — Damage is — and will become more —dangerous before long-term solutions are effective
+ Warming is already dangerous, likely to reach 1.5°C by 2030 (#2), 2°C before 2050 (#5) and 3–5°C by 2100 on the current path (#9).
+ This will trigger more large system tipping points and brings unacceptable risks of a “Hothouse Earth” scenario (#10).
+ Mitigation is vital but will not have noticeable beneficial impact on temperature trajectory till mid-2040s due to concurrent aerosol loss (#3).
+ This delay in mitigation effect may trigger further significant physical tipping points.
+ Zero emissions, even in a decade, coupled with large-scale drawdown, is not sufficient to negate the existential risk (#13).
+ Solar radiation management (SRM), such as deployment of cooling aerosols in the upper atmosphere, can have a strong, immediate cooling effect.
+ There is no current evidence that SRM would demonstrate a net environmental and social benefit, but if proven it may be considered an interim cooling measure whilst longer-acting solutions are deployed and take effect. 
+ There are global SRM governance issues and risks to navigate in order to prevent unilateral deployment by national actors and misuse. 
19/ Adaptation actions should protect the most vulnerable — Adaptation is vital, but no substitute for deep climate mitigation
+ Adaptation should be seen as a parallel strategy to mitigation to deal with unavoidable impacts and risks.
+ It is no substitute for deep climate mitigation and restoration because it is not possible for most people and nature to adapt to 3–5°C of warming this century (#9 and #11).
+ There is the danger of the “adaptation trap”, where most effort is put into adaptation, and the lack of adequate mitigation delivers a “hothouse Earth”.
+ Adaptation should prioritize actions to protect the most vulnerable human populations and nature.
+ We should strengthen the capacity and skills required by people to face climate disruption with honesty, courage and compassion.
20/ The collapse of civilization is not inevitable, but emergency-level action right now is critical — An emergency response would make climate the number one priority of politics and economics
+ Many human and Earth systems are increasingly fragile.
+ The end of civilization due to climate disruption — the generalized collapse of contemporary societies — is not certain or inevitable.
+ But it is likely unless dramatic global action is taken to make climate the number one priority of economics and politics in an emergency response.
+ But large-scale disruption is inevitable, either by failing to act fast enough, or because the scale of action now required is far beyond a gradualist approach.
+ The short term is crucial: what we do now and before 2030 matters, not aspirations about 2050.
SUMMARY – Overview and key points
+ 1.5°C around or before 2030, irrespective of actions taken in the interim, and a decade ahead of IPCC projections.
+ Even substantial emission reductions will have no significant impact on the warming trend over the next 20-25 years, due to the offsetting effect of aerosols.
+ 2°C is likely prior to 2050, even with actions better than the current Paris Agreement commitments, and 3°C in the early-to-mid second half of the century on current emissions trajectory, with 5°C possible by 2100.
+ The current 1.2°C of warming is already dangerous; 2°C would be extremely dangerous; 3°C catastrophic; and 4°C unlivable for most people.
+ A “Hothouse Earth”, non-linear, irreversible, self-sustaining warming may be triggered between 1.5–2°C. There is a risk that we have already lost control of the system.
RESPONSES & ACTIONS
+ Societies that are successfully overcoming the Covid pandemic threat are doing so by making it the highest priority of politics and economics, based upon acceptance of the best available science. Climate is a much bigger threat, that requires the same approach.
+ Assess the real risks with brutal, rigorous honesty.
+ Recognize that climate disruption requires an emergency, planned response.
+ Act fast for zero emissions by 2030.
+ Build capacity to draw down carbon.
+ Understand what role solar radiation management may play.
+ Making action on climate disruption the first priority of government is the key to protecting people, society and nature
1 NASA Global Land-ocean Temperature Index Dataset (1951-2020).
2 Based on 5-year average for second half of each decade, from NASA dataset: 2005-2009 (above 1880-1909) 0.89°C; 2015-2019 1.16°C.
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13 CO2e — or carbon dioxide equivalent — is an estimate of the effect of the well-mixed greenhouse gases, including methane and nitrous oxide, measured as a carbon dioxide equivalent, in parts per million (ppm).
14 Based on ΔT=ECS*log(CO2t/280) where ECS is climate sensitivity and CO2t is total well-mixed greenhouse gases in parts per million.
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17 Chart courtesy Glen Peters, based on data from GCP and CDIAC.
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Q1 Prof. Hans joachim schellnhuber Director emeritus of the potsdam institute. Breeze, N, 2019, ’It’s nonlinearity – stupid!’, The Ecologist, 3 January.
Q2 António Guterres UN Secretary General, 30 June 2019. United Nations, 2019, ‘Secretary-General’s remarks to Climate Summit Preparatory Meeting’, United Nations, 30 June.
Q3 Vinke, K et al, 2020, ‘Corona and the climate: a comparison of two emergencies’, Global Sustainability 3, e25, 1–7.
Q3 Rowling, M, 2019, ‘UN climate chief says 3C hotter world “just not possible”’, Thomson Reuters News, 17 June.
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