A reader shares a report: The last fully intact ice shelf in the Canadian Arctic has collapsed, losing more than 40% of its area in just two days at the end of July, researchers said on Thursday. The Milne Ice Shelf is at the fringe of Ellesmere Island, in the sparsely populated northern Canadian territory of Nunavut. "Above normal air temperatures, offshore winds and open water in front of the ice shelf are all part of the recipe for ice shelf break up," the Canadian Ice Service said on Twitter when it announced the loss on Sunday. "Entire cities are that size. These are big pieces of ice," said Luke Copland, a glaciologist at the University of Ottawa who was part of the research team studying the Milne Ice Shelf. The shelf's area shrank by about 80 square kilometers. By comparison, the island of Manhattan in New York covers roughly 60 square kilometers.

"This was the largest remaining intact ice shelf, and it's disintegrated, basically," Copland said. The Arctic has been warming at twice the global rate for the last 30 years, due to a process known as Arctic amplification. But this year, temperatures in the polar region have been intense. The polar sea ice hit its lowest extent for July in 40 years. Record heat and wildfires have scorched Siberian Russia. Summer in the Canadian Arctic this year in particular has been 5 degrees Celsius above the 30-year average, Copland said. That has threatened smaller ice caps, which can melt quickly because they do not have the bulk that larger glaciers have to stay cold. As a glacier disappears, more bedrock is exposed, which then heats up and accelerates the melting process.

An anonymous reader quotes a report from CBS News: Alarming heat scorched Siberia on Saturday as the small town of Verkhoyansk (67.5N latitude) reached 100.4 degrees Fahrenheit, 32 degrees above the normal high temperature. If verified, this is likely the hottest temperature ever recorded in Siberia and also the hottest temperature ever recorded north of the Arctic Circle, which begins at 66.5 degrees North. The town is 3,000 miles east of Moscow and further north than even Fairbanks, Alaska. On Friday, the city of Caribou, Maine, tied an all-time record at 96 degrees Fahrenheit and was once again well into the 90s on Saturday. To put this into perspective, the city of Miami, Florida, has only reached 100 degrees one time since the city began keeping temperature records in 1896.

Verkhoyansk is typically one of the coldest spots on Earth. This past November, the area reached nearly 60 degrees Fahrenheit below zero, one of the first spots to drop that low in the winter of 2019-2020. Reaching 100 degrees in or near the Arctic is almost unheard of. Although the reading is questionable, back in 1915 the town of Fort Yukon, Alaska, not quite as far north as Verkhoyansk, is reported to have reached near 100 degrees. And in 2010 a town a few miles south of the Arctic circle in Russia reached 100. As a result of the hot-dry conditions right now, numerous fires rage nearby, and smoke is visible for thousands of miles on satellite images.

An anonymous reader quotes a report from The Guardian: There was a dramatic melting of Greenland's ice sheet in the summer of 2019, researchers have confirmed, in a study that reveals the loss was largely down to a persistent zone of high pressure over the region. The ice sheet melted at a near record rate in 2019, and much faster than the average of previous decades. Figures have suggested that in July alone surface ice declined by 197 gigatons -- equivalent to about 80 million Olympic swimming pools. Now experts have examined the level of melting in more detail, revealing what drove it. Crucially, the team note, the high pressure conditions lasted for 63 of the 92 summer days in 2019, compared with an average of just 28 days between 1981 and 2010. A similar situation was seen in 2012, a record bad year for melting of the ice sheet.

Writing in the journal the Cryosphere, [researchers] report how they used satellite data, climate models and global weather patterns to explore the melting of the surface of the ice sheet last year. Among their findings the team report that almost 96% of the ice sheet underwent melting at some time in 2019, compared with an average of just over 64% between 1981 and 2010. Using models, the pair also found that about 560Gt of meltwater runoff was generated in the summer of 2019. The surface mass balance, the amount of ice the sheet gained from rain and snowfall minus the amount lost through meltwater run off and evaporation, was just 54Gt a year -- about 320Gt a year lower than the average across the earlier decades, and the greatest such drop on record. Further analysis showed the level and distribution of melting to be closely tied to a number of factors, including levels of snowfall and reflection of sunlight -- known as albedo -- as well as cloudiness and absorption of sunlight. All of these, they note, were influenced by the persistent high pressure zone over the ice sheet last summer.

The 2010s were the hottest decade ever measured on Earth, and 2019 was the second-hottest year ever measured, scientists at NASA and the National Oceanic and Atmospheric Administration announced today. From a report: After a year of flash droughts, rampant wildfires, and searing heatwaves that set all-time records across Europe and turned parts of Greenland's ice sheet into slush, the finding was not a surprise to researchers, or likely anyone else. But it capped an anxious decade that saw human-caused climate change transform from a far-off threat to an everyday fact of life. Last year was 1.8 degree Fahrenheit -- or just under one degree Celsius -- warmer than the 20th century average, Gavin Schmidt, the chief climate scientist at NASA, said at a briefing announcing the news. Almost everywhere on the planet's surface was warmer than average, though the Arctic was especially searing. "Every decade since the 1960s has been warmer than the decade previous," he said.

In short, it's bad, but you probably knew that already. At least four different groups of scientists, each working independently, have now concluded that the 2010s were the hottest decade of the modern era. (NASA and NOAA start this era at 1880, when they say weather record-keeping became reliable and widespread enough to trust, but the nonprofit research agency Berkeley Earth argues that 2019 was the second warmest year since at least 1850.) What's worse is that greenhouse-gas pollution from fossil fuels, which are the biggest driver of climate change, also surged to an all-time high last year, according to a preliminary estimate. Deke Arndt, a chief climate scientist at NOAA, said at a briefing today that "an obvious signal" of this greenhouse-gas-powered heating had appeared in the upper layers of the ocean, which broke the all-time heat record last year.

An anonymous reader quotes a report from The Guardian: Greenland's ice sheet is melting much faster than previously thought, threatening hundreds of millions of people with inundation and bringing some of the irreversible impacts of the climate emergency much closer. Ice is being lost from Greenland seven times faster than it was in the 1990s, and the scale and speed of ice loss is much higher than was predicted in the comprehensive studies of global climate science by the Intergovernmental Panel on Climate Change, according to data. That means sea level rises are likely to reach 67cm by 2100, about 7cm more than the IPCC's main prediction. Such a rate of rise will put 400 million people at risk of flooding every year, instead of the 360 million predicted by the IPCC, by the end of the century.

Greenland has lost 3.8 trillion tons of ice since 1992, and the rate of ice loss has risen from 33 billion tons a year in the 1990s to 254 billion tons a year in the past decade. Greenland's ice contributes directly to sea level rises as it melts because it rests on a large land mass, unlike the floating sea ice that makes up much of the rest of the Arctic ice cap. About half of the ice loss from Greenland was from melting driven by air surface temperatures, which have risen much faster in the Arctic than the global average, and the rest was from the speeding up of the flow of ice into the sea from glaciers, driven by the warming ocean. The scale and speed of the ice loss surprised the team of 96 polar scientists behind the findings, published on Tuesday in the journal Nature. The Ice Sheet Mass Balance Inter-comparison Exercise comprised 26 separate surveys of Greenland from 1992 to 2018, with data from 11 different satellites and comparisons of volume, flow and gravity compiled by experts from the UK, Nasa in the US, and the European Space Agency.

sciencehabit writes: Climate change doubters have a favorite target: climate models. They claim that computer simulations conducted decades ago didn't accurately predict current warming, so the public should be wary of the predictive power of newer models. Now, the most sweeping evaluation of these older models -- some half a century old -- shows most of them were indeed accurate. "How much warming we are having today is pretty much right on where models have predicted," says the study's lead author, Zeke Hausfather, a graduate student at the University of California, Berkeley.

The researchers compared annual average surface temperatures across the globe to the surface temperatures predicted in 17 forecasts. Those predictions were drawn from 14 separate computer models released between 1970 and 2001. In some cases, the studies and their computer codes were so old that the team had to extract data published in papers, using special software to gauge the exact numbers represented by points on a printed graph. Most of the models accurately predicted recent global surface temperatures, which have risen approximately 0.9C since 1970. For 10 forecasts, there was no statistically significant difference between their output and historic observations, the team reports today in Geophysical Research Letters. Seven older models missed the mark by as much as 0.1C per decade. But the accuracy of five of those forecasts improved enough to match observations when the scientists adjusted a key input to the models: how much climate-changing pollution humans have emitted over the years.

An anonymous reader quotes a report from CBS News: Last month was the hottest ever October on record globally, according to data released Friday by the Copernicus Climate Change Service, an organization that tracks global temperatures. The month, which was reportedly 1.24 degrees Fahrenheit warmer than the average October from 1981-2010, narrowly beat October 2015 for the top spot. According to Copernicus, most of Europe, large parts of the Arctic and the eastern U.S. and Canada were most affected. The Middle East, much of Africa, southern Brazil, Australia, eastern Antarctica and Russia also experienced above-average temperatures. Parts of tropical Africa and Antarctica and the western U.S. and Canada felt much colder than usual, however. While all major oceans experienced unusually low temperatures, air temperatures over the sea were still much higher than average.

October is following a 2019 trend. The hottest-ever September follows a record-setting summer, which included the hottest-ever June and July and the second-hottest August. Overall, 2019 will make history as one of the top five warmest years on record, according to the National Oceanic and Atmospheric Association. Temperatures from November 2018 to October 2019 were above average for "virtually all of Europe," and most other areas of land and ocean, Copernicus said.

An anonymous reader quotes a report from The Guardian: Growing demand for SUVs was the second largest contributor to the increase in global CO2 emissions from 2010 to 2018, an analysis has found. In that period, SUVs doubled their global market share from 17% to 39% and their annual emissions rose to more than 700 megatons of CO2, more than the yearly total emissions of the UK and the Netherlands combined. No energy sector except power drove a larger increase in carbon emissions, putting SUVs ahead of heavy industry (including iron, steel, cement and aluminum), aviation and shipping.

The recent dramatic shift towards heavier SUVs has offset both efficiency improvements in smaller cars and carbon savings from electric vehicles. As the global fleet of SUVs has grown, emissions from the vehicles have increased more than fourfold in eight years. If SUV drivers were a nation, they would rank seventh in the world for carbon emissions. T&E figures show the average mass of new cars rose 10% between 2000 and 2016, which the group suggested could be down to a trend towards SUVs, heavier automatic and dual-clutch gearboxes and the inclusion of other equipment including cameras and sensors.

An anonymous reader quotes a report from Phys.Org: Greenhouse gases thrust into the atmosphere mainly by burning fossil fuels are warming Earth's surface more quickly than previously understood, according to new climate models set to replace those used in current UN projections, scientists said Tuesday. By 2100, average temperatures could rise 7.0 degrees Celsius above pre-industrial levels if carbon emissions continue unabated, separate models from two leading research centers in France showed. That is up to two degrees higher than the equivalent scenario in the Intergovernmental Panel for Climate Change's (IPCC) 2014 benchmark 5th Assessment Report.

The new calculations also suggest that the Paris Agreement goals of capping global warming at "well below" two degrees, and 1.5C if possible, will be challenging at best, the scientists said. "With our two models, we see that the scenario known as SSP1 2.6 -- which normally allows us to stay under 2C -- doesn't quite get us there," Olivier Boucher, head of the Institute Pierre Simon Laplace Climate Modeling Center in Paris, told AFP. A new generation of 30-odd climate models known collectively as CMIP6 -- including the two unveiled Tuesday -- will underpin the IPCC's next major report in 2021.

Kate Marvel, writing for Scientific American: We are, I promise you, not doomed, no matter what Jonathan Franzen says. We could be, of course, if we decided we really wanted to. We have had the potential for total annihilation since 1945, and the capacity for localized mayhem for as long as societies have existed. Climate change offers the easy choice of a slow destruction through inaction like the proverbial frog in the slowly boiling pot. And there are times when the certainty of inevitability seems comforting. Fighting is exhausting; fighting when victory seems uncertain or unlikely even more so. It's tempting to retreat to a special place -- a cozy nook, a mountaintop, a summer garden -- wait for the apocalypse to run its course, and hope it will be gentle.

[...] It is precisely the fact that we understand the potential driver of doom that changes it from a foregone conclusion to a choice, a terrible outcome in the universe of all possible futures. I run models through my brain; I check them with the calculations I do on a computer. This is not optimism, or even hope. Even in the best of all possible worlds, I cannot offer the certainty of safety. Doom is a possibility; it may that we have already awakened a sleeping monster that will in the end devour the world. It may be that the very fact of human nature, whatever that is, forecloses any possibility of concerted action. But I am a scientist, which means I believe in miracles. I live on one. We are improbable life on a perfect planet. No other place in the universe has nooks or perfect mountaintops or small and beautiful gardens. A flower in a garden is an exquisite thing, rooted in soil formed from old rocks broken by weather. It breathes in sunlight and carbon dioxide and conjures its food as if by magic. For the flower to exist, a confluence of extraordinary things must happen. It needs land and air and light and water, all in the right proportion, and all at the right time. Pick it, isolate it, and watch it wither. Flowers, like people, cannot grow alone.

European climate researchers said Monday that last month was the hottest July -- and thus the hottest month -- ever recorded (Warning: source may be paywalled; alternative source), slightly eclipsing the previous record-holder, July 2016. "While July is usually the warmest month of the year for the globe, according to our data it also was the warmest month recorded globally, by a very small margin," Jean-Noel Thepaut, head of the Copernicus Climate Change Service, said in a statement. The New York Times reports: The service, part of an intergovernmental organization supported by European countries, said the global average temperature last month was about 0.07 degree Fahrenheit (0.04 Celsius) hotter than July 2016. The researchers noted that their finding was based on analysis of only one of several data sets compiled by agencies around the world. The climate service noted some regional temperature differences in July. Western Europe was above average, in part because of a heat wave that occurred during the last week of the month and set temperature records in Germany, the Netherlands and elsewhere. A rapid analysis released last week found that climate change made the heat wave more likely. "The highest above-average conditions were recorded across Alaska, Greenland and large swathes of Siberia," the report adds. "Large parts of Africa and Australia were warmer than normal, as was much of Central Asia. Cooler than average temperatures prevailed in Eastern Europe, much of Asia, the Northern Plains and Pacific Northwest of the United States and over large parts of Western Canada."

According to data from the Mauna Loa Observatory in Hawaii, the concentration of CO2 in the atmosphere is over 415 parts per million (ppm), far higher than at any point in the last 800,000 years, since before the evolution of homo sapiens. From a report: Holthaus spotted the new high on Sunday when it was tweeted out by the Scripps Institution of Oceanography, which measures daily CO2 rates at Mauna Loa along with scientists from the National Oceanic and Atmospheric Administration. Measurements have been ongoing since the program was started in 1958 by the late Charles David Keeling, for whom the Keeling Curve, a graph of increasing CO2 concentration in the atmosphere, is named. "This is the first time in human history our planet's atmosphere has had more than 415ppm CO2," Holthaus said in a widely shared tweet. "Not just in recorded history, not just since the invention of agriculture 10,000 years ago. Since before modern humans existed millions of years ago," added Holthaus.

The string of hotter-than-average annual temperatures continued in 2018, as Earth experienced its fourth-hottest year on record, according to NASA and the National Oceanic and Atmospheric Administration [PDF]. From a report: Also in 2018, the United States suffered 14 weather and climate disasters with costs surpassing $1 billion during a warmer- and wetter-than-average year, NOAA reports. Global temperatures across land and sea were 1.42 degrees Fahrenheit above the 20th century average, making 2018 the fourth-warmest year since record-keeping began in 1880, NOAA said in a report Thursday. In a separate report, NASA's Goddard Institute for Space Studies said global temperatures were 1.5 degrees above the 1951 to 1980 mean, also the fourth highest going back to 1880.

The 2-degrees Fahrenheit increase in global temperatures since the late 19th century has been driven largely by growing carbon dioxide and other greenhouse gas emissions from human activity, said the institute's director, Gavin Schmidt. The conclusion reaffirms NASA's long-established finding that man-made emissions are driving climate change, which President Donald Trump and some senior administration officials frequently challenge. By both agencies' measures, Earth has now recorded its five hottest annual average temperatures in the past five years. "2018 is yet again an extremely warm year on top of a long-term global warming trend," Schmidt said in a press release.

An anonymous reader shares a report: More Americans are very worried about global warming and say the issue is personally important to them than ever before, according to a new poll released Tuesday. The polling may indicate that extreme weather events -- coupled with a series of grim scientific findings -- over the past year are starting to change peoples' minds about climate change, which could have significant implications for any significant climate legislation passing Congress. The key finding from the new survey from the Yale Program on Climate Change Communication and the George Mason University Center for Climate Change Communication is that Americans increasingly view global warming as a present-day threat to them, rather than an issue that will affect future generations. Nearly half of Americans (46%) said they personally experienced the effects of global warming -- a 15-point spike since March 2015.

Hurricane Harvey swamped Houston with seven days of pounding rain last August. When scientists went back to look at historical weather patterns, they reported Harvey dumped 20 percent more rain than it typically would have. The culprit: climate change. From a report: High-resolution climate simulations of 15 tropical cyclones in the Atlantic, Pacific and Indian Oceans found that warming in the ocean and atmosphere increased rainfall by between 5% and 10%, although wind speeds remained largely unchanged. This situation is set to worsen under future anticipated warming, however. Researchers found that if little is done to constrain greenhouse gas emissions and the world warms by 3C to 4C this century then hurricane rainfall could increase by a third, while wind speeds would be boosted by as much as 25 knots.

"Climate change has exacerbated rainfall and is set to enhance the wind speed," said Christina Patricola, who undertook the study with her Lawrence Berkeley National Laboratory colleague Michael Wehner. "My hope is that this information can be used to improve our resilience to the kinds of extreme weather events we are going to have in the future." The research, published in the journal Nature, used climate models to see how factors such as air and ocean temperatures have influenced hurricanes. Projections into the future were then made, based upon various levels of planetary warming. The findings suggest that enormously destructive storms have already been bolstered by climate change and similar events in the future are on course to be cataclysmic.