Major U.N. climate change report warns of “extreme” and “unprecedented” impacts

The United Nations’ climate science panel issued its much anticipated special report on climate impacts and transformation on Friday, calling for urgent action to avoid the “severe, pervasive and irreversible impacts” of global warming.

The United Nations released a report on climate change developments around the globe. It is called “Sovereign risks in a low carbon world”. The report says that climate change will lead to a 1.5 degree Celsius rise in temperature by 2100. The report warns of “extreme” and “unprecedented” impacts on the planet.

The Intergovernmental Panel on Climate Change (IPCC) released its latest report today, which predicts some “unprecedented” and “extreme” impacts of global warming.

From floods to fires, the summer of 2021 has been marked by unprecedented extremes across the world, indicating that climate change’s effects are already pervasive and increasing. Such extremes, and their link to human-caused climate change, are only one of the major themes of the United Nations’ Intergovernmental Panel on Climate Change’s historic climate report published Monday (IPCC).

It is part of the IPCC’s Sixth Assessment Study, which is the most important climate report released by the worldwide scientific community in years. It was written by more than 230 top scientists from across the globe.

The paper is a compilation of research from over 14,000 sources. It’s essentially a climate science encyclopedia, including a description of the most recent scientific consensus on climate change and what the future holds, based on advanced climate models and historical data. It’s an update on how the Earth’s climate and our knowledge of it have evolved since the previous report, which was released in 2013.

“Human impact has unmistakably warmed the atmosphere, oceans, and land,” the study says. Many of the changes that have been wrought on the globe — particularly in our seas — will be “irreversible for decades to millennia,” according to the report, and continuing warming would hasten the occurrence of “extreme occurrences unparalleled in the observational record.”

“The alarm bells are blaring, and the data is irrefutable: greenhouse gas emissions from fossil fuel burning and deforestation are strangling our planet and putting billions of people in imminent danger,” said UN Secretary General Antonio Guterres, according to CBS News’ Pamela Falk.

However, the study also conveys the awareness that there is still time to address the climate problem. The study emphasizes that every degree of warming counts, and that less warming will assist to avert catastrophe. This will need actions such as decreasing methane emissions and greenhouse gas emissions in the near future. According to the study, science indicates that if humanity can continue on a low-carbon path in the future, it would “deliver fast and persistent benefits to prevent human-caused climate change.”

The United Nations has a new headquarters. Extreme weather climate report 04:43

Professor Ed Hawkins of the University of Reading in the United Kingdom, one of the report’s lead authors, says the report’s main messages are that “climate change is indisputably caused by human activities (primarily fossil fuel burning and deforestation), and that this is already affecting every region, including making extreme weather events worse.”

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“To prevent global temperature increase, immediate, fast, and persistent reductions in greenhouse gas emissions are needed,” he added.

Unprecedented transformations

Since the 1800s, scientists have known that gases like carbon dioxide warm the earth by trapping heat. By the 1960s, scientists and even Big Oil corporations had realized that increasing atmospheric greenhouse gases by burning fossil fuels had negative repercussions for the world.

As the warning signals of climate change grew increasingly visible, the worldwide community decided to unite to confront the problem. The IPCC was established in 1988 by the World Meteorological Organization and the United Nations Environmental Program. It is an international organization made up of scientists and politicians charged with presenting objective research on climate change and explaining the dangers, implications, and potential solutions to the globe. Since 1990, the IPCC has published full assessment reports every few years, with special reports in between.

This year’s report, like the last one in 2013, leaves no doubt in the minds of doubters, saying unequivocally that human activities have caused global warming. “Widespread and fast changes” have already happened, and their effects are being felt all across the globe.

Due to human-caused warming, “large-scale markers of climate change in the atmosphere, ocean, and cryosphere [frozen regions] are reaching levels, and changing at speeds unseen in hundreds to many thousands of years,” the scientists write.

The following are some of the major findings:

Carbon dioxide (CO2) levels in the atmosphere are now greater than they have been in the previous 2 million years. It’s at least 800,000 years for methane. And, during the same time span, the rate of growth in greenhouse gases outpaces all natural variations.

As a consequence, temperatures have risen at a greater pace in the past 50 years than at any other period in the last 2,000 years. In the period 2011–2020, the average global surface temperature was 1.1° Celsius (2° Fahrenheit) higher than it was between 1850 and 1900 (before human activity began warming the globe), with greater warming over land (1.6°C) than over the ocean (0.9°C). The most recent decade is expected to be the warmest since the previous interglacial era, which occurred 125,000 years ago.

The melting of ice is occurring at unprecedented rates in contemporary times due to rising temperatures. The amount of Arctic sea ice in late summer is lower than it has been in the previous 1,000 years. Since the 1950s, nearly all of the world’s glaciers have been receding at the same time, which is unprecedented in the past 2,000 years.

The seas are changing dramatically as a result of greenhouse gas emissions, warming, and ice melt from land. The current pace of sea level rise is the fastest in at least 3,000 years. Between 1901 and 2018, the global mean sea level rose by approximately 8 inches. Between 1901 and 1971, the rate of growth was 1.3 millimeters per year, while between 2006 and 2018, it rose to 3.7 millimeters per year.

Our seas retain 90 percent of the surplus heat trapped in the Earth system. As a consequence, the ocean is accumulating heat at a rate unprecedented since the end of the last Ice Age.

When carbon dioxide dissolves in saltwater, it causes the ocean to become more acidic, endangering coral and other marine life. According to the study, ocean acidification has reached “unprecedented levels in the last 2 million years.”

Extreme weather and climate change

“Human-induced climate change is already influencing numerous weather and climate extremes in every area throughout the world,” according to this year’s study, which discusses severe weather.

More heat waves, heavier rains, more severe storms, droughts, and compound occurrences, in which the effects of several catastrophes pile on top of one other, are all being driven by a changing climate.

And, according to the study, things are just going to get worse. It predicts “extreme occurrences unparalleled in the observational record” with 1.5°C of global warming, which we will likely reach in the 2030s.

The most apparent link between global warming and heat waves is the occurrence of heat waves. Since the 1950s, they have grown “more frequent and more severe over most geographical regions,” according to the study. Recent extremes would have been “extremely unlikely to occur without human influence on the climate system,” according to the report, which also notes that marine heat waves, defined as abnormally high temperatures in ocean waters, have nearly doubled since the 1980s, with human fingerprints on the majority of them.

As the temperature of the air rises, the atmosphere can retain more moisture, resulting in greater rainfall. As a consequence, the frequency and severity of heavy precipitation occurrences have risen since 1950.

Droughts are being exacerbated by climate change, which is frequently caused by increased evaporation from soils and plants.

Tropical cyclones and hurricanes are changing as ocean temperatures rise and more atmospheric moisture becomes accessible. Over the past four decades, the worldwide percentage of big storms (Category 3–5) has risen, and climate change has increased the heavy precipitation associated with them.

Extreme weather is a warning that the climate crisis is becoming worse… 06:11

How much warmer will future climate scenarios be?

A suite of climate models is run for each IPCC assessment cycle to help forecast our changing climate into the future. These models have evolved through time to become increasingly complex and high-resolution. The Coupled Model Intercomparison Project (CMIP6), which includes approximately 100 climate models from 50 distinct worldwide modeling organizations, is the name of the project.

The reduction of the range of warming predicted from doubling atmospheric carbon dioxide (CO2) concentrations in the atmosphere — a concept known as Equilibrium Climate Sensitivity — is a significant achievement for this year’s study (ECS). The ECS varied between 1.5°C and 4.5°C in the last study, indicating a significant range of uncertainty that may result in drastically different climatic consequences.

Scientists were able to decrease the ECS uncertainty to a best estimate of 3°C of warming, with a probable range of 2.5°C to 4°C, thanks to better model output.

The modelers performed a set of five emissions scenarios for this report cycle to see how the climate will react to different amounts of greenhouse gas emissions, land use changes, and air pollution. Solar activity and volcanoes are also taken into consideration in the models. These scenarios are intended to show how our decisions influence the planet’s future.

Despite the fact that the IPCC does not comment on the plausibility of any particular scenario, it is widely accepted that the lowest and highest emissions scenarios are improbable and serve as a lower and upper limit on potential climatic futures. Everything depends on humanity’s response to climate change, or lack thereof.

The study finds that, under all emission scenarios, global surface temperature would continue to rise until at least the middle of this century, based on these models. Unless “significant reductions in carbon dioxide and other greenhouse gas emissions in the next decades,” the Paris Agreement’s objective of no more than 1.5°C or 2°C over pre-industrial levels would be surpassed throughout the twenty-first century.

Depending on which scenario is closer to reality, there is a broad range of potential warming (as shown in the chart below). Warming may remain close to 1.5°C in a scenario where CO2 emissions are drastically and quickly cut. However, in a very high emissions scenario, temperature may reach as high as 5.7°C, which would be disastrous.

Both possibilities are very improbable, according to experts. An intermediate scenario with warming closer to 3°C is the most probable result.

In any event, all five scenarios are projected to meet or surpass 1.5°C global warming compared to 1850-1900 levels, and this will happen before 2040. Temperatures exceed the 1.5°C target in the highest emissions scenarios. However, there is only a short overshoot of the target in the lowest emissions scenario.

In terms of the 2°C warming goal, all three higher emissions scenarios result in the target being breached. Warming will almost certainly be limited to less than 2°C under the two lowest emission scenarios.

These many scenarios demonstrate that mankind has the ability to minimize the worst effects of climate change if we chose to do so collectively.

Impacts are uneven: it’s hotter, wetter, and drier.

You can see how various areas of the Earth are expected to warm at different degrees of global warming in the maps below. The Arctic, which is warming three times faster than the rest of the world, will continue to set the pace. And land areas – where people live — will continue to warm faster than the water, with various regions being impacted.

 

Overall, the Earth will get wetter, while certain regions will become drier. Throughout decades of climate modeling, these wet and dry patterns have remained mostly constant. This is related to the water cycle being more intense and current weather patterns. It’s obvious that high latitudes and monsoon regions in Africa and India will get drier, resulting in floods in places that aren’t equipped for such extremes.

Meanwhile, regions prone to water stress and fire will continue to suffer from the effects of the drought. The Southwest United States, Central America, the Amazon, southern Africa, the Mediterranean, and the Middle East are among these regions. Water shortages and out-of-control wildfires have afflicted all of these regions, and the trend is expected to continue.

One thing that has been clearly apparent in recent years is that as temperatures increase, severe weather becomes more probable, and in certain instances, at an increasing pace. This is particularly true during periods of severe heat. Even with apparently small increases in global warming, the frequency and severity of heat waves will continue to rise.

Extreme heat events, such as those that occurred once every 50 years in the globe before climate change, have already risen by approximately 5 times. As the world warms, situations like this will become more common.

Rainfall has a direct relationship with the temperature of the atmosphere, and the study predicts that heavy precipitation events will become more intense and frequent in the future. Heavy rain occurrences have risen by approximately 50% in the Northeast United States.

Because a warmer climate accelerates the water cycle, not only heavy precipitation but also drought will become more common. Though average precipitation will rise in most areas, strong rain episodes will provide more precipitation than moderate rainfall spread out over time.

Drought has a greater effect because higher heat energy in the system leads to more evaporation, which dries up plants and soils. The consequence may be seen in the West, where a naturally dry long-term trend has combined with climate change to drive the worst two decades of drought in over a century since 2000.

Heavy precipitation and drought events that would normally occur once every ten years in a particular area will become more common as a result of global warming. As temperatures rise, the amount of precipitation falls steadily, but it’s important emphasizing that the biggest precipitation events, such as the catastrophic floods that hit Western Europe last summer, could increase much quicker, exceeding current infrastructure.

180 people have died as a result of the worst floods in Europe’s history at 02:18.

The report’s warning regarding storm patterns is particularly worrisome as we near the height of hurricane season, especially considering the monster storms of recent hurricane seasons.

“With increasing global warming, the proportion of intense tropical cyclones (categories 4-5) and peak wind speeds of the most intense tropical cyclones are projected to increase at the global scale,” it says, though it adds that the science on whether the number of tropical systems will increase or decrease is still unclear.

Additional warming in the colder areas will inevitably result in increased permafrost melting and the loss of seasonal snow cover, land ice, and sea ice. The Arctic is expected to be almost ice-free in September (when it hits its annual low) at least once before 2050 under all of the emission scenarios.

The fact that ice reflects the sun’s rays back into space and helps prevent warmer air and water from reaching the Arctic adds to the effect of ice melt. As a result, the loss of ice works as a self-reinforcing feedback loop, increasing warming. Another feedback that will grow when permafrost thaws is the release of long-trapped greenhouse gases.

07:49 Arctic study portrays bleak climate scenario

The effects on the seas will be felt for generations.

While it will be essential to restrict warming in order to maintain Earth’s capacity to sustain life in the future, some changes have already been baked into the system and are irreversible on century time periods. Because the ocean accumulates, circulates, and releases heat over far longer periods, even if we cease warming today, the oceans will continue to rise and the ice will continue to melt.

“Sea level is set to increase for decades to millennia as a result of continued deep ocean warming and ice sheet melt,” the study states, “and will stay high for thousands of years.”

For example, we know from paleoclimatology, which utilizes data from the fossil record like as ice cores, tree rings, and ocean sediments, that sea levels were considerably higher than they are now 125,000 years ago, during the Ice Ages, but temperatures were about the same. As a result of the ongoing glacier melt, sea levels are expected to increase for hundreds of years, ultimately reaching levels last seen during that time period.

Global sea level is expected to rise by up to 2.5 feet by 2100 and over 4 feet by 2150 under the report’s intermediate emissions scenario. That’s without taking into account the possibility of ice sheets collapsing in Greenland or Antarctica, which is becoming more likely as the world warms.

According to the study, global mean sea level would increase up to 10 feet in the next 2,000 years if warming is restricted to 1.5°C, or up to 20 feet if warming exceeds 2°C.

But it becomes much worse if we exceed the climate goals set forth in the Paris Agreement. Then there’s the climate millions of years ago, when sea levels were perhaps more than 70 feet greater than they are now.

“As a paleoclimate scientist, I see lots of evidence that climate can change dramatically when it’s pushed. Humans are pushing the climate. There’s no going back, but we could limit the worst effects if we make major rapid reductions in greenhouse gas emissions,” Darrell S. Kaufman, a paleoclimatologist at Northern Arizona University who studies past climate stretching back millions of years, told CBS News.

The report’s examination of so-called low-likelihood but high-impact catastrophes, such as ice sheet collapse or sudden changes in ocean circulation, is perhaps the most concerning element. Although the likelihood or timing of these events cannot be predicted with any degree of certainty, the study states that they cannot be ruled out and must be included as part of our risk assessment.

A possible tipping point in the Atlantic Ocean current system known as the Atlantic Meridional Overturning Circulation, or AMOC, which has been deteriorating or may potentially be on the verge of collapse, is one example of such an occurrence. The system, which brings colder water south in deeper currents and circulates warmer water northward from the tropics, has far-reaching impacts on weather patterns over most of the world.

This has been causing increasing worry. Only a few years ago, the IPCC believed that a breakdown in this vital ocean circulation would take hundreds of years, but they are no longer so confident. The AMOC is now “extremely likely to deteriorate throughout the twenty-first century for all emission scenarios,” according to the scientists, who can only state that “there is medium confidence that there will not be a sudden collapse before 2100.”

If such a collapse occurred, it would very certainly result in major changes in regional weather patterns and the water cycle, with broad and significant effects on rainfall and drought.

The present system’s slowdown may have global implications… 08:28

“It’s a fixable issue,” says the narrator, “but there’s no time to spare.”

Last week, the Summary for Policy Makers section of the report was completed in a marathon session in which delegates from 195 member nations weighed in and agreed on the final wording.

“Every single phrase is discussed in incredible depth by the official delegations,” Hawkins said. “There is frequently some compromise between the different delegations on the precise choice of words — it is their summary for policymakers, so it must include the information that is relevant for governments — but the scientists always have the final say; if the wording is not consistent with the underlying scientific assessment, the discussions continue until it is.”

“The language is fairly harsh for an IPCC report,” Hawkins says, noting that some of the final phrasing may not be as strong as many in the scientific community would want.

Andrew Dessler, a climate professor at Texas A&M University, told CBS News that there’s a good reason countries have to unanimously agree on every sentence of the Summary for Policy Makers.

Dessler says, “These papers serve as the beginning point for climate talks.” “Given the SPM process, no nation can subsequently claim that they don’t agree with the research; they’ve already agreed to it.”

While our climate reality is full of dread and gloom, the study emphasizes that we still have a limited amount of time to avoid the worst consequences.

The authors argue that doing so “means reducing cumulative CO2 emissions, achieving at least net zero CO2 emissions, and significant reductions in other greenhouse gas emissions.”

Methane, which has approximately 80 times the warming potential of carbon dioxide during the first 20 years, is the greenhouse gas with the most immediate effect. Methane levels have been significantly increasing in recent years as a result of natural gas and animal emissions. As a result, the study urges for “significant, fast, and long-term reductions in CH4 [methane] emissions.”

The graph below helps put the task’s size into perspective. Humans have released about 2,600 gigatons of carbon since humans first began using fossil fuels. We can only emit another 400 gigatons to keep warming below 1.5°C, which we will accomplish in 9 years or fewer if we continue on our current path. It’s a near-impossible job to do. We have another 1,150 gigatons to prevent 2°C warming, which would take another 26 years at present rates. Most experts believe that it is possible, but it will need a lot of teamwork and determination.

Breaching any of these Paris Agreement goals would not lead to a climate cliff, but as the world warms, the effects will progressively exceed the earth’s human life-support systems — particularly if they occur at the same time. As a result, every fraction of a degree counts.

According to the study, choosing the low-emissions scenario over the high-emissions scenario would result in a “noticeable change” in temperature trends in approximately 20 years. Low-emission scenarios “would have fast and persistent impacts to prevent human-caused climate change,” according to the study.

The fact that temperature rises in a linear manner with increases in greenhouse gases is comforting news confirmed in this study. This implies that if we cease putting carbon into the atmosphere, the Earth’s temperature will soon stabilize.

Despite decades of warnings, emissions and temperatures continue to accelerate at an alarming rate.

“It’s like we’re on a speeding train barreling towards a brick wall, and it doesn’t matter whether we hit that wall at 200 mph or 20 mph,” says Kendra Pierre-Louis, a climate journalist who works on the climate solutions podcast “How to Save a Planet.”

“Perfect is the enemy of good. The best climate issue to tackle is the one you can tackle provided you link it to systemic changes,” she said, offering as an example: “It is good to ride a bicycle. You can feel virtuous. But it’s better to push for the infrastructure to get say half your town out of cars, and onto a bike or walking or on transit.”

Pierre-Louis was asked by CBS News what message she thinks the IPCC report would convey. “I want people to realize that it’s a solved issue,” she responded.

“If we join forces immediately, we can avoid climate disaster,” UN Secretary General Antonio Guterres said in a statement. “But, as today’s report makes clear, there is no time for delay and no place for excuses.”

A major new United Nations report on climate change has warned that the world is facing a “climate emergency” that will threaten people’s health, food security and livelihoods unless urgent action is taken to reduce greenhouse gas emissions.. Read more about ipcc climate change report 2021 and let us know what you think.

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