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Climate change widespread, rapid, and intensifying
by Intergovernmental Panel on Climate Change
6:25pm 15th Sep, 2021
 
25 Oct. 2021
  
Ongoing rises in greenhouse gas concentrations jeopardizes Paris Agreement temperature targets. (WMO)
  
The abundance of heat-trapping greenhouse gases in the atmosphere once again reached a new record last year, with the annual rate of increase above the 2011-2020 average. That trend has continued in 2021, according to the World Meteorological Organization (WMO) Greenhouse Gas Bulletin.
  
Concentration of carbon dioxide (CO2), the most important greenhouse gas, reached 413.2 parts per million in 2020 and is 149% of the pre-industrial level. Methane (CH4) is 262% and nitrous oxide (N2O) is 123% of the levels in 1750 when human activities started disrupting Earth’s natural equilibrium.
  
The economic slowdown from COVID-19 did not have any discernible impact on the atmospheric levels of greenhouse gases and their growth rates.
  
As long as emissions continue, global temperature will continue to rise. Given the long life of CO2, the temperature level already observed will persist for several decades even if emissions were to rapidly reduce to net zero.
  
Alongside rising temperatures, this means more weather extremes including intense heat and rainfall, ice melt, sea-level rise and ocean acidification, accompanied by far-reaching socioeconomic impacts.
  
Roughly half of the CO2 emitted by human activities today remains in the atmosphere. The other half is taken up by oceans and land ecosystems. The Bulletin flagged concern that the ability of land ecosystems and oceans to act as “sinks” may become less effective in future, thus reducing their ability to absorb carbon dioxide and act as a buffer against larger temperature increase.
  
The Bulletin shows that from 1990 to 2020, radiative forcing – the warming effect on our climate - by long-lived greenhouse gases increased by 47%, with CO2 accounting for about 80% of this increase. The numbers are based on monitoring by WMO’s Global Atmosphere Watch network.
  
“The Greenhouse Gas Bulletin contains a stark, scientific message for climate change negotiators at COP26. At the current rate of increase in greenhouse gas concentrations, we will see a temperature increase by the end of this century far in excess of the Paris Agreement targets of 1.5 degrees Celsius above pre-industrial levels,” said WMO Secretary-General Prof. Petteri Taalas. “We are way off track.”
  
“The amount of CO2 in the atmosphere breached the milestone of 400 parts per million in 2015. And just five years later, it exceeded 413 ppm. This is more than just a chemical formula and figures on a graph. It has major negative repercussions for our daily lives and well-being, for the state of our planet and for the future of our children and grandchildren,” said Prof. Taalas.
  
“Carbon dioxide remains in the atmosphere for centuries and in the ocean for even longer. The last time the Earth experienced a comparable concentration of CO2 was 3-5 million years ago, when the temperature was 2-3°C warmer and sea level was 10-20 meters higher than now. But there weren’t 7.8 billion people then,” said Prof. Taalas.
  
“Many countries are now setting carbon neutral targets (for the distant future of 2050 and 2060, when immediate action is demanded now, with at a minimum 50% reductions in green gas emissions by 2030) and it is hoped that COP26 will see a dramatic increase in commitments. We need to transform our commitment into action that will have an impact of the gases that drive climate change. We need to revisit our industrial, agricultural, energy and transport systems and whole way of life. The needed changes are economically affordable and technically possible. There is no time to lose,” said Prof. Taalas.
  
http://public.wmo.int/en/media/press-release/state-of-climate-2021-extreme-events-and-major-impacts http://public.wmo.int/en/media/press-release/greenhouse-gas-bulletin-another-year-another-record http://www.unep.org/news-and-stories/press-release/updated-climate-commitments-ahead-cop26-summit-fall-far-short-net http://www.unep.org/news-and-stories/press-release/governments-fossil-fuel-production-plans-dangerously-out-sync-paris http://productiongap.org/2021report/ http://www.ipcc.ch/report/sixth-assessment-report-working-group-i/
  
7 Oct. 2021
  
Unprecedented rise of heat and rainfall extremes in observational data - Potsdam Institute for Climate Research
  
A 90-fold increase in the frequency of monthly heat extremes in the past ten years compared to 1951-1980 has been found by scientists in observation data. Their analysis reveals that so-called 3-sigma heat events, which deviate strongly from what is normal in a given region, now on average affect about 9 percent of all land area at any time.
  
Record daily rainfall events also increased in a non-linear way – on average, 1 in 4 rainfall records in the last decade can be attributed to climate change. Already today, extreme events linked to human-caused climate change are at unprecedented levels, the scientists say, and they must be expected to increase further.
  
“For extreme extremes, what we call 4-sigma-events that have been virtually absent before, we even see a roughly 1000-fold increase compared to the reference period. They affected about 3 percent of global land area in 2011-20 in any month,” says lead-author Alexander Robinson from Complutense University of Madrid, Spain, and Potsdam Institute for Climate Impact Research, Germany. “This confirms previous findings, yet with ever-increasing numbers. We are seeing extremes now which are virtually impossible without the influence of global warming caused by greenhouse gas emissions from burning fossil fuels.”
  
The term ‘sigma’ refers to what scientists call a standard deviation. For example, 2020 brought prolonged heat waves to both Siberia and Australia, contributing to the emergence of devastating wildfires in both regions. Both events led to the declaration of a local state of emergency.
  
Temperatures at life-threatening levels have hit parts of the US and Canada in 2021, reaching almost 50°C. Globally, the record-breaking heat extremes increased most in tropical regions, since these normally have a low variability of monthly temperatures. As temperatures continue to rise, however, record-breaking heat will also become much more common".
  
Small temperature increase, disproportionally big consequences
  
Comparing the new data with the already quite extreme previous decade of 2000-2010, the data show that the land area affected by heat extremes of the 3-sigma category roughly doubled. Those deviations which are so strong they have previously been essentially absent, the 4-sigma events, newly emerged in the observations. Rainfall records have increased a further 5 percentage points in the last decade. The seemingly small amount of warming in the past ten years, just 0.25°C, has thus pushed up climate extremes substantially.
  
“These data show that extremes are now far outside the historical experience. Extreme heat and extreme rainfall are increasing disproportionally,” says co-author Stefan Rahmstorf, from the Potsdam Institute for Climate Impact Research. “Our analysis confirms once again that for the impacts of global heating on us humans, every tenth of a degree matters.”
  
http://www.pik-potsdam.de/en/news/latest-news/unprecedented-rise-of-heat-and-rainfall-extremes-in-observational-data
  
* Climate change could bring near-unliveable conditions for 3 billion people by 2070, say scientists. Each degree of warming above present levels corresponds to roughly 1bn people falling outside of ‘climate niche’: http://www.pnas.org/content/117/21/11350
  
28 Sep. 2021
  
Young climate activists Greta Thunberg and Vanessa Nakate have condemned global leaders' response to the planetary crisis, with Thunberg calling it "a betrayal of all present and future generations."
  
"Our leaders are lost," said Nakate from Uganda, "and our planet is damaged."
  
Their blunt remarks came in keynote addresses at the opening of the three-day Youth4Climate summit in Milan. Hundreds of young people are gathered there for in-person working groups to finalise proposals to present to ministers at the Pre-COP in Milan later this month and COP 26 United Nations climate talks starting next month in Glasgow.
  
Simply focusing on adaptation measures, as Nakate put it, amounts to climate injustice. "You cannot adapt to starvation. You cannot adapt to extinction," she said. "How long must children sleep hungry because their farms have been washed away, because their crops have been dried up because of the extreme weather conditions?" she asked attendees.
  
"How long are we to watch them die of thirst and gasp for air in the floods? World leaders watch this happen and allow this to continue."
  
"Why is it so easy for leaders to open up new coal power plants, construct oil pipelines, and extract gas—which are all destroying our climate," Nakate said, "but so hard for them to acknowledge that loss and damage is here with us now?"
  
"Climate action is not a pick-and-choose," she continued, referencing the need to avert future impacts but also "deal with the loss and damage that is already happening."
  
"It's time for leaders to put loss and damage at the center of negotiation," said Nakate. "It's time to acknowledge that there's need for additional funding on top of what has already been promised for the most vulnerable. It's time for our leaders to wake up!"
  
"It’s time to show us the money," she said. "It's time, it's time, it's time."
  
Swedish climate campaigner Greta Thunberg slammed governments for "shamelessly congratulating themselves" for insufficient pledges to cut emissions and promises of financing. "There is no Planet B, there is no planet blah, blah, blah," Thunberg said to warm applause.
  
Echoing a speech by COP26 summit host Boris Johnson in April, she continued: "This is not about some expensive politically correct dream of bunny hugging, or build back better, blah blah blah, green economy, blah blah blah, net zero by 2050, blah blah blah, climate neutral blah blah blah.
  
"This is all we hear from our so-called leaders: words, words that sound great but so far have led to no action, our hopes and dreams drowned in their empty words and promises," said Thunberg. "Our leaders' intentional lack of action is a betrayal of all present and future generations," said Thunberg.
  
She said governments had been "shamelessly congratulating themselves while still failing to come up with the long overdue funding" for developing nations.
  
"It's time for our leaders to stop talking and start acting, it's time for the polluters to pay, it's time to keep promises," said Nakate. "No more empty promises, no more empty summits, no more empty conferences. It's time to show us the money."
  
http://fridaysforfuture.org/ http://all4climate2021.org/ http://www.unicef.org/press-releases/one-billion-children-extremely-high-risk-impacts-climate-crisis-unicef http://resourcecentre.savethechildren.net/library/born-climate-crisis-why-we-must-act-now-secure-childrens-rights http://www.savethechildren.net/news/climate-crisis-710-million-children-live-countries-high-risk http://www.ipcc.ch/report/ar6/wg1/
  
http://www.bmj.com/content/374/bmj.n1734 http://www.noaa.gov/news/its-official-july-2021-was-earths-hottest-month-on-record http://www.pik-potsdam.de/en/news/latest-news/today2019s-children-to-experience-two-to-seven-times-more-extremes-than-their-grandparents http://www.theguardian.com/commentisfree/2021/oct/21/climate-leaders-cop26-uk-climate-crisis-glasgow http://www.carbonbrief.org/analysis-which-countries-are-historically-responsible-for-climate-change http://climateactiontracker.org/publications/global-update-september-2021/ http://ipbes.net/news/Media-Release-Global-Assessment http://ipbes.net/global-assessment
  
Climate change widespread, rapid, and intensifying. (IPCC News)
  
Scientists are observing changes in the Earth’s climate in every region and across the whole climate system, according to the latest Intergovernmental Panel on Climate Change (IPCC) Report, released today.
  
Many of the changes observed in the climate are unprecedented in thousands, if not hundreds of thousands of years, and some of the changes already set in motion—such as continued sea level rise—are irreversible over hundreds to thousands of years.
  
However, strong and sustained reductions in emissions of carbon dioxide (CO2) and other greenhouse gases would limit climate change.
  
While benefits for air quality would come quickly, it could take 20-30 years to see global temperatures stabilize, according to the IPCC Working Group I report, Climate Change 2021: the Physical Science Basis, approved on Friday by 195 member governments of the IPCC, through a virtual approval session that was held over two weeks starting on July 26.
  
The Working Group I report is the first instalment of the IPCC’s Sixth Assessment Report (AR6), which will be completed in 2022.
  
“This report reflects extraordinary efforts under exceptional circumstances,” said Hoesung Lee, Chair of the IPCC. “The innovations in this report, and advances in climate science that it reflects, provide an invaluable input into climate negotiations and decision-making.”
  
Faster warming
  
The report provides new estimates of the chances of crossing the global warming level of 1.5°C in the next decades, and finds that unless there are immediate, rapid and large-scale reductions in greenhouse gas emissions, limiting warming to close to 1.5°C or even 2°C will be beyond reach.
  
The report shows that emissions of greenhouse gases from human activities are responsible for approximately 1.1°C of warming since 1850-1900, and finds that averaged over the next 20 years, global temperature is expected to reach or exceed 1.5°C of warming.
  
This assessment is based on improved observational datasets to assess historical warming, as well progress in scientific understanding of the response of the climate system to human-caused greenhouse gas emissions.
  
“This report is a reality check,” said IPCC Working Group I Co-Chair Valérie Masson-Delmotte. “We now have a much clearer picture of the past, present and future climate, which is essential for understanding where we are headed, what can be done, and how we can prepare.”
  
Every region facing increasing changes
  
Many characteristics of climate change directly depend on the level of global warming, but what people experience is often very different to the global average. For example, warming over land is larger than the global average, and it is more than twice as high in the Arctic.
  
“Climate change is already affecting every region on Earth, in multiple ways. The changes we experience will increase with additional warming,” said IPCC Working Group I Co-Chair Panmao Zhai.
  
The report projects that in the coming decades climate changes will increase in all regions.
  
For 1.5°C of global warming, there will be increasing heat waves, longer warm seasons and shorter cold seasons. At 2°C of global warming, heat extremes would more often reach critical tolerance thresholds for agriculture and health, the report shows.
  
But it is not just about temperature. Climate change is bringing multiple different changes in different regions – which will all increase with further warming. These include changes to wetness and dryness, to winds, snow and ice, coastal areas and oceans. For example:
  
Climate change is intensifying the water cycle. This brings more intense rainfall and associated flooding, as well as more intense drought in many regions.
  
Climate change is affecting rainfall patterns. In high latitudes, precipitation is likely to increase, while it is projected to decrease over large parts of the subtropics. Changes to monsoon precipitation are expected, which will vary by region.
  
Coastal areas will see continued sea level rise throughout the 21st century, contributing to more frequent and severe coastal flooding in low-lying areas and coastal erosion. Extreme sea level events that previously occurred once in 100 years could happen every year by the end of this century.
  
Further warming will amplify permafrost thawing, and the loss of seasonal snow cover, melting of glaciers and ice sheets, and loss of summer Arctic sea ice.
  
Changes to the ocean, including warming, more frequent marine heatwaves, ocean acidification, and reduced oxygen levels have been clearly linked to human influence.
  
These changes affect both ocean ecosystems and the people that rely on them, and they will continue throughout at least the rest of this century.
  
For cities, some aspects of climate change may be amplified, including heat (since urban areas are usually warmer than their surroundings), flooding from heavy precipitation events and sea level rise in coastal cities.
  
For the first time, the Sixth Assessment Report provides a more detailed regional assessment of climate change, including a focus on useful information that can inform risk assessment, adaptation, and other decision-making, and a new framework that helps translate physical changes in the climate – heat, cold, rain, drought, snow, wind, coastal flooding and more – into what they mean for society and ecosystems.
  
This regional information can be explored in detail in the newly developed Interactive Atlas interactive-atlas.ipcc.ch as well as regional fact sheets, the technical summary, and underlying report.
  
Human influence on the past and future climate
  
“It has been clear for decades that the Earth’s climate is changing, and the role of human influence on the climate system is undisputed,” said Masson-Delmotte.
  
Yet the new report also reflects major advances in the science of attribution – understanding the role of climate change in intensifying specific weather and climate events such as extreme heat waves and heavy rainfall events.
  
The report also shows that human actions still have the potential to determine the future course of climate. The evidence is clear that carbon dioxide (CO2) is the main driver of climate change, even as other greenhouse gases and air pollutants also affect the climate.
  
“Stabilizing the climate will require strong, rapid, and sustained reductions in greenhouse gas emissions, and reaching net zero CO2 emissions. Limiting other greenhouse gases and air pollutants, especially methane, could have benefits both for health and the climate,” said Zhai.
  
http://www.ipcc.ch/report/ar6/wg1/ http://www.ipcc.ch/2021/08/09/ar6-wg1-20210809-pr/ http://www.unep.org/resources/report/climate-change-2021-physical-science-basis-working-group-i-contribution-sixth http://news.un.org/en/story/2021/08/1097362
  
Sep. 2021
  
Climate crisis: Over 200 health journals urge world leaders to tackle “catastrophic harm”
  
The UN General Assembly in September 2021 will bring countries together at a critical time for marshalling collective action to tackle the global environmental crisis. They will meet again at the biodiversity summit in Kunming, China, and the climate conference (COP26) in Glasgow, UK.
  
Ahead of these pivotal meetings, we—the editors of health journals worldwide—call for urgent action to keep average global temperature increases below 1.5°C, halt the destruction of nature, and protect health.
  
Health is already being harmed by global temperature increases and the destruction of the natural world, a state of affairs health professionals have been bringing attention to for decades. The science is unequivocal; a global increase of 1.5°C above the pre-industrial average and the continued loss of biodiversity risk catastrophic harm to health that will be impossible to reverse.
  
Despite the world’s necessary preoccupation with covid-19, we cannot wait for the pandemic to pass to rapidly reduce emissions.
  
Reflecting the severity of the moment, this editorial appears in health journals across the world. We are united in recognising that only fundamental and equitable changes to societies will reverse our current trajectory.
  
The risks to health of increases above 1.5°C are now well established. Indeed, no temperature rise is “safe.” In the past 20 years, heat related mortality among people aged over 65 has increased by more than 50%.
  
Higher temperatures have brought increased dehydration and renal function loss, dermatological malignancies, tropical infections, adverse mental health outcomes, pregnancy complications, allergies, and cardiovascular and pulmonary morbidity and mortality.
  
Harms disproportionately affect the most vulnerable, including children, older populations, ethnic minorities, poorer communities, and those with underlying health problems.
  
Global heating is also contributing to the decline in global yield potential for major crops, falling by 1.8-5.6% since 1981; this, together with the effects of extreme weather and soil depletion, is hampering efforts to reduce undernutrition.
  
Thriving ecosystems are essential to human health, and the widespread destruction of nature, including habitats and species, is eroding water and food security and increasing the chance of pandemics.
  
The consequences of the environmental crisis fall disproportionately on those countries and communities that have contributed least to the problem and are least able to mitigate the harms.
  
Yet no country, no matter how wealthy, can shield itself from these impacts. Allowing the consequences to fall disproportionately on the most vulnerable will breed more conflict, food insecurity, forced displacement, and zoonotic disease—with severe implications for all countries and communities. As with the covid-19 pandemic, we are globally as strong as our weakest member.
  
Rises above 1.5°C increase the chance of reaching tipping points in natural systems that could lock the world into an acutely unstable state. This would critically impair our ability to mitigate harms and to prevent catastrophic, runaway environmental change.
  
Global targets are not enough
  
Encouragingly, many governments, financial institutions, and businesses are setting targets to reach net-zero emissions, including targets for 2030. The cost of renewable energy is dropping rapidly. Many countries are aiming to protect at least 30% of the world’s land and oceans by 2030.
  
These promises are not enough. Targets are easy to set and hard to achieve. They are yet to be matched with credible short and longer term plans to accelerate cleaner technologies and transform societies. Emissions reduction plans do not adequately incorporate health considerations.
  
Concern is growing that temperature rises above 1.5°C are beginning to be seen as inevitable, or even acceptable, to powerful members of the global community.
  
Relatedly, current strategies for reducing emissions to net zero by the middle of the century implausibly assume that the world will acquire great capabilities to remove greenhouse gases from the atmosphere.
  
This insufficient action means that temperature increases are likely to be well in excess of 2°C, a catastrophic outcome for health and environmental stability. Critically, the destruction of nature does not have parity of esteem with the climate element of the crisis, and every single global target to restore biodiversity loss by 2020 was missed. This is an overall environmental crisis.
  
Health professionals are united with environmental scientists, businesses, and many others in rejecting that this outcome is inevitable. More can and must be done now—in Glasgow and Kunming—and in the immediate years that follow. We join health professionals worldwide who have already supported calls for rapid action.
  
Equity must be at the centre of the global response. Contributing a fair share to the global effort means that reduction commitments must account for the cumulative, historical contribution each country has made to emissions, as well as its current emissions and capacity to respond.
  
Wealthier countries will have to cut emissions more quickly, making reductions by 2030 beyond those currently proposed and reaching net-zero emissions before 2050. Similar targets and emergency action are needed for biodiversity loss and the wider destruction of the natural world.
  
To achieve these targets, governments must make fundamental changes to how our societies and economies are organised and how we live.
  
The current strategy of encouraging markets to swap dirty for cleaner technologies is not enough. Governments must intervene to support the redesign of transport systems, cities, production and distribution of food, markets for financial investments, health systems, and much more.
  
Global coordination is needed to ensure that the rush for cleaner technologies does not come at the cost of more environmental destruction and human exploitation.
  
Many governments met the threat of the covid-19 pandemic with unprecedented funding. The environmental crisis demands a similar emergency response. Huge investment will be needed, beyond what is being considered or delivered anywhere in the world.
  
But such investments will produce huge positive health and economic outcomes. These include high quality jobs, reduced air pollution, increased physical activity, and improved housing and diet. Better air quality alone would realise health benefits that easily offset the global costs of emissions reductions.
  
These measures will also improve the social and economic determinants of health, the poor state of which may have made populations more vulnerable to the covid-19 pandemic.
  
But the changes cannot be achieved through a return to damaging austerity policies or the continuation of the large inequalities of wealth and power within and between countries.
  
Cooperation hinges on wealthy nations doing more
  
In particular, countries that have disproportionately created the environmental crisis must do more to support low and middle income countries to build cleaner, healthier, and more resilient societies. High income countries must meet and go beyond their outstanding commitment to provide $100bn a year, making up for any shortfall in 2020 and increasing contributions to and beyond 2025.
  
Funding must be equally split between mitigation and adaptation, including improving the resilience of health systems.
  
Financing should be through grants rather than loans, building local capabilities and truly empowering communities, and should come alongside forgiving large debts, which constrain the agency of so many low income countries. Additional funding must be marshalled to compensate for inevitable loss and damage caused by the consequences of the environmental crisis.
  
As health professionals, we must do all we can to aid the transition to a sustainable, fairer, resilient, and healthier world. Alongside acting to reduce the harm from the environmental crisis, we should proactively contribute to global prevention of further damage and action on the root causes of the crisis.
  
We must hold global leaders to account and continue to educate others about the health risks of the crisis. We must join in the work to achieve environmentally sustainable health systems before 2040, recognising that this will mean changing clinical practice.
  
Health institutions have already divested more than $42bn of assets from fossil fuels; others should join them.
  
The greatest threat to global public health is the continued failure of world leaders to keep the global temperature rise below 1.5°C and to restore nature.
  
Urgent, society-wide changes must be made and will lead to a fairer and healthier world. We, as editors of health journals, call for governments and other leaders to act, marking 2021 as the year that the world finally changes course.
  
http://www.bmj.com/content/374/bmj.n1734 http://www.who.int/news/item/11-10-2021-who-s-10-calls-for-climate-action-to-assure-sustained-recovery-from-covid-19 http://www.who.int/publications/i/item/cop26-special-report http://www.thelancet.com/journals/lancet/article/PIIS0140-6736(21)01787-6/fulltext
  
Aug. 2021
  
Major climate changes inevitable and irreversible – IPCC’s starkest warning yet. (Guardian News)
  
Report warns temperatures likely to rise by more than 1.5C bringing widespread extreme weather
  
Human activity is changing the Earth’s climate in ways “unprecedented” in thousands or hundreds of thousands of years, with some of the changes now inevitable and “irreversible”, climate scientists have warned.
  
Within the next two decades, temperatures are likely to rise by more than 1.5C above pre-industrial levels, breaching the ambition of the 2015 Paris climate agreement, and bringing widespread devastation and extreme weather.
  
Only rapid and drastic reductions in greenhouse gases in this decade can prevent such climate breakdown, with every fraction of a degree of further heating likely to compound the accelerating effects, according to the International Panel on Climate Change, the world’s leading authority on climate science.
  
The comprehensive assessment of climate science published on Monday, the sixth such report from the IPCC since 1988, has been eight years in the making, marshalling the work of hundreds of experts and peer-review studies. It represents the world’s full knowledge to date of the physical basis of climate change, and found that human activity was “unequivocally” the cause of rapid changes to the climate, including sea level rises, melting polar ice and glaciers, heatwaves, floods and droughts.
  
The Secretary Genral of the United Nations and a number of Government leaders say the stark findings must force new policy measures as a matter of urgency, to shift the global economy to a low-carbon footing.
  
Governments from 197 countries will meet this November in Glasgow for vital UN climate talks, called Cop26. Each nation is asked to come to Cop26 with fresh plans to reduce greenhouse gas emissions to a level that will limit global heating to no more than 1.5C above pre-industrial levels, the ambition of the Paris climate agreement and a goal the IPCC emphasised was still possible, but only just.
  
António Guterres, the UN secretary-general, warned: “This report is a code red for humanity. The alarm bells are deafening, and the evidence is irrefutable: greenhouse gas emissions from fossil fuel burning and deforestation are choking our planet and putting billions of people at immediate risk.”
  
He called for an end to new coal plants and to new fossil fuel exploration and development, and for governments, investors and businesses to pour all their efforts into a low-carbon future. “This report must sound a death knell for coal and fossil fuels, before they destroy our planet,” he said.
  
Temperatures have now risen by about 1.1C since the period 1850 to 1900, but stabilising the climate at 1.5C was still possible, the IPCC said. That level of heating would still result in increasing heatwaves, more intense storms, and more serious droughts and floods, but would represent a much smaller risk than 2C.
  
Richard Allan, a professor of climate science at Reading University, and an IPCC lead author, said each fraction of a degree of warming was crucial. “You are promoting moderate extreme weather events to the premier league of extreme events [with further temperature rises],” he said.
  
Civil society groups urged governments to act without delay. Doug Parr, chief scientist at Greenpeace UK, said: “This is not the first generation of world leaders to be warned by scientists about the gravity of the climate crisis, but they’re the last that can afford to ignore them. The increasing frequency, scale and intensity of climate disasters that have scorched and flooded many parts of the world in recent months is the result of past inaction. Unless world leaders finally start to act on these warnings, things will get much, much worse.”
  
Stephen Cornelius, chief adviser on climate change at WWF, added: “This is a stark assessment of the frightening future that awaits us if we fail to act. With the world on the brink of irreversible harm, every fraction of a degree of warming matters to limit the dangers.”
  
Even if the world manages to limit warming to 1.5C, some long-term impacts of warming already in train are likely to be inevitable and irreversible. These include sea level rises, the melting of Arctic ice, and the warming and acidification of the oceans. Drastic reductions in emissions can stave off worse climate change, according to IPCC scientists, but will not return the world to the more moderate weather patterns of the past.
  
Ed Hawkins, a professor of climate science at the University of Reading, and a lead author for the IPCC, said: “We are already experiencing climate change, including more frequent and extreme weather events, and for many of these impacts there is no going back.”
  
This report is likely to be the last report from the IPCC while there is still time to stay below 1.5C, added Joeri Rogelj, director of research at the Grantham Institute, Imperial College London, and an IPCC lead author.
  
“This report shows the closer we can keep to 1.5C, the more desirable the climate we will be living in, and it shows we can stay within 1.5C but only just – only if we cut emissions in the next decade,” he said. “If we don’t, by the time of the next IPCC report at the end of this decade, 1.5C will be out the window.”
  
http://www.theguardian.com/science/2021/aug/09/humans-have-caused-unprecedented-and-irreversible-change-to-climate-scientists-warn http://www.bbc.com/news/science-environment-58130705 http://www.washingtonpost.com/climate-environment/2021/08/10/ipcc-report-un-takeaways/ http://wapo.st/3l4AYiJ http://www.noaa.gov/news/its-official-july-2021-was-earths-hottest-month-on-record

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