donsutherland1

IMO, this study by Dr. Zhu, Dr. Tierney et al., is particularly important. The newer climate models have been showing greater warming than the prior ones for the expected RCPs. A better handle on cloud-related feedbacks, not modeling error, might be producing this outcome.

As the world's youth engage in demonstrations to break the unwillingness of policy makers to meaningfully launch a sustained effort to address the challenge of anthropogenic climate change, some of those with high profiles in the shrinking movement that rejects the overwhelming and unequivocal basis of climate change, are now launching broad ad hominem attacks against the youth, particularly 16-year-old Swede Greta Thunberg. One denier, who has no known medical degree or any expertise in the field of psychiatry, diagnosed 16-year-old Greta Thunberg, who has galvanized the international youth movement, as "mentally ill." Another dehumanized her, labeling her a "puppet" while gloating about rising global greenhouse gas emissions. Yet another mocked her as a child who enjoys "sacred status" only due to her youth. What do these ad hominem attacks by such climate change deniers as Bjorn Lomborg, Steve Milloy, and Tom Nelson say? First, they demonstrate that they lack credible evidence or knowledge to rebut the overwhelming and unequivocal body of scientific evidence for anthropogenic climate change. They cannot explain the observed warming. They cannot escape the reality that solar irradiance has not increased to produce such warming. Second, it reveals that individuals who have less exposure to the consequences of climate change than the youth simply don't care about the future to which they seek to confine the world's young people and succeeding generations. After all, by the end of the 21st century when the consequences of climate change will be growing ever more severe, those reactionaries will have long departed this world. Third, it potentially says a lot about their character and who they are as people. A recent article published in The New Republic explains the underlying dynamic that may be driving those who engage in the nasty attacks aimed at tearing down the youth, a disproportionate share of whom are female, leading today's climate change movement. As Thunberg approached America, she was followed by a tsunami of male rage. On her first day of sailing, a multi-millionaire Brexit activist tweeted that he wished a freak accident would destroy her boat. A conservative Australian columnist called her a “deeply disturbed messiah of the global warming movement,” while the British far-right activist David Vance attacked the “sheer petulance of this arrogant child.” While these examples might feel like mere coincidence to some, the idea that white men would lead the attacks on Greta Thunberg is consistent with a growing body of research linking gender reactionaries to climate-denialism... In 2014, Jonas Anshelm and Martin Hultman of Chalmers published a paper analyzing the language of a focus group of climate skeptics. The common themes in the group, they said, were striking: “for climate skeptics … it was not the environment that was threatened, it was a certain kind of modern industrial society built and dominated by their form of masculinity.” The connection has to do with a sense of group identity under threat, Hultman told me—an identity they perceive to be under threat from all sides. Besieged, as they see it, both by developing gender equality—Hultman pointed specifically to the shock some men felt at the #MeToo movement—and now climate activism’s challenge to their way of life, male reactionaries motivated by right-wing nationalism, anti-feminism, and climate denialism increasingly overlap, the three reactions feeding off of one another. That reactionaries would assail those leading a reform movement is not new. When Martin Luther King, Jr. was leading the American Civil Rights movement during the 1960s, he and many of those involved in the movement, encountered vicious attacks aimed at delegitimizing the movement and violence aimed at suppressing it altogether. Once one looks beyond the noise and ugliness of the dying climate change denial movement of today, there is reason for optimism. Today's engaged youth appear to be embarked in sustained pursuit of a long-term goal supported by overwhelming empirical evidence. In other words, the movement won't end with today's demonstration. Today's youth have also demonstrated a capacity to leverage the Internet and Social Media to organize intensively across national borders to take on what is a global, not national, challenge. This capacity will serve them well as they become of voting age and enter the political realm. That advancing scientific knowledge has prevailed across time offers the prospect that the youth will ultimately prevail in their cause. Perhaps in decades from now, just as the Segregationists were permanently discarded onto the proverbial trash heap of history, so will the climate deniers, particularly those who engaged in the vile and reprehensible conduct cited in the above examples. In stark contrast, just as Martin Luther King, Jr.'s place in history as a reformer who advanced human welfare is secure, the place of Greta Thunberg, among the other organizers of today's demonstrations, will also be secure. Most importantly, the world will be far better off from the courage, effort, and persistence of the youth who made that better world possible.

That the climate is dynamic (has always changed and would continually change absent an anthropogenic influence) does not mean that humans aren't the predominant driver of the contemporary change. The evidence of the dramatic ongoing warming and the anthropogenic nature are overwhelming and unequivocal. Solar irradiance has not materially increased since 1950. Global temperatures have decoupled from solar irradiance. Unlike with a solar driver, where all levels of the atmosphere warm on account of an increase in incoming shortwave radiation, the stratosphere has been cooling while the troposphere has been warming. That is a classic fingerprint of greenhouse gases emitting some of the earth's outgoing longwave radiation back to the surface. This imbalance is leading to warming. http://www.ces.fau.edu/nasa/module-2/how-greenhouse-effect-works.php The physical properties of carbon dioxide were discovered back in the 19th century. Their atmospheric concentration has increased dramatically from 316 ppm in 1959 to just under 409 ppm in 2018 at the Mauna Loa Observatory. No natural variables can explain this increase. Human emissions, not all of which are absorbed by carbon sinks, do. When atmospheric greenhouse gases are included, the recent warming is represented very well. There is a very high coefficient of determination between the greenhouse gases and temperature (as one would expect from the demonstrated physical properties of such gases). https://climexp.knmi.nl/imageoftheweek.png This strong relationship is part of the reason the shrinking minority who rejects the reality of anthropogenic climate change often attempt to discredit the temperature records. They have no scientifically-valid alternative explanation for the warming. Hence, they try to get around that barrier by discounting or denying the warming. Of course, even if no temperature record existed, trends in declining Arctic sea ice, migration of flora, general retreat of glaciers, rising sea level, etc., are all consistent with a warming world.

Yesterday, Utqiagvik (formerly Barrow) experienced its first freeze of the season. That was its latest freeze on record. The prior record was September 7, 2009. As a result, that city's 85-consecutive day stretch above freezing ended. The old record was 68 consecutive days, set in 2009. Both records are likely, in large part, due to low Arctic sea ice.

On September 19, Arctic sea ice extent rose further to 4.010 million square kilometers on JAXA. It is possible that the minimum extent for 2019 has been reached. Whether that is, in fact the case, will become evident in coming days.

November 22.

Arctic Sea Ice Extent: September 18, 2019 vs. September 18, 1989: Source: NSIDC

I provided one paper earlier that dealt with the accuracy issue. The temperature data can be relied on with a very high degree of confidence. At 2 sigma (> 95% confidence), the error is around 0.1°C (e.g., for GISS). Thus, for example, the decadal average mean anomaly during the last 10 years on GISS (+0.78°C) clearly was warmer than that during the 1990s (+0.39°C). The difference between the two 10-year periods was so great that one was dealing with > 99.9% confidence. Statistically, arguments that the 1990s were just as warm (or warmer) are inaccurate.

Global average temperatures and anomalies are not a single area temperature/anomaly. They are measured in thousands of areas on land and in the ocean. Thus, the hypothetical scenario, which was meant to illustrate the concept of averages in thousandths of degrees, is spot on.

Temperatures approached daily record low figures in parts of the Northeast this morning. Overall, many areas in the Middle Atlantic and southern New England regions experienced their coldest readings so far this fall. Low temperatures included: Albany: 42° (lowest since May 14); Binghamton: 42° (lowest since June 4); Boston: (lowest since May 29); Bridgeport: 47° (lowest since June 4); Danbury: 36° (lowest since April 29); Islip: 46° (lowest since June 4); New York City: 52° (lowest since May 16); Newark: 49° (lowest since May 15); Philadelphia: 53° (lowest since June 15); Poughkeepsie: 38° (lowest since April 29); Providence: 45° (lowest since May 15); and, White Plains: 43° (lowest since May 15). In the wake of this recent fairly sharp cool shot, temperatures will rebound starting tomorrow. A warmer to much warmer than normal weekend lies ahead. The ENSO Region 1+2 anomaly was -1.3°C and the Region 3.4 anomaly was -0.3°C for the week centered around September 11. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.65°C and the ENSO Region 3.4 anomaly has averaged -0.03°C. There remains uncertainty about the ENSO evolution later this fall. Despite the guidance, the strong cooling in Region 1+2 indicates that the prospects for a neutral-cool ENSO during the winter have increased. Such a scenario may be somewhat more likely than not. That outcome could have significant winter season implications. Since 1991 when weekly ENSO region data was available, six years have seen September record 2 or more weeks with -1.0°C or cooler weekly anomalies in Region 1+2: 1996, 1999, 2002, 2007, 2010, and 2017. 5/6 (83%) of those cases went on to feature warm December-February temperature anomalies in the Middle Atlantic and southern New England regions. 2002 had one such week ahead of what would evolve into an El Niño winter. The SOI value was -35.30 today. Often an SOI figure at or below -30.00 during the second half of September has been followed by a warmer than normal October. 2002, which saw severe October blocking during which the Arctic Oscillation fell to as low as -5.098 on October 18, was an exception. Today, the preliminary Arctic Oscillation (AO) figure was -1.061. A sharp rebound will very likely commence tomorrow. Since 1950, there have been five prior cases when the AO averaged -0.500 or below in both July and August: 1950, 1958, 1960, 1968, and 2015. The average temperature for September was 69.1° (69.8° after adjusting for ongoing warming) and 58.9° (59.6° adjusted) for September through November in New York City. The 1981-2010 baseline normal figures are 68.0° and 57.5° respectively. The majority of cases saw a warmer than normal September and all cases featured a warmer than normal fall. Among those five cases, 2015 made a transition from predominantly negative AO values to predominantly positive ones during the fall. The combination of the AO's recent increase to the strongest positive values since April and some of the extended range guidance leave open a scenario where the AO is currently in the early stages of evolving to a predominantly positive regime. Such an outcome would also favor a warmer than normal fall and possible warm start to winter in the Middle Atlantic and southern New England regions. For now, this is merely a hypothetical discussion of one potential path toward winter. Many other variables are involved. The only idea that carries weight at this time is that the possible evolution reaffirms the longstanding signal for a warm fall. Therefore, a warmer than normal September and fall appear likely. The potential for autumn 2019 to rank among the 30 warmest cases on record remains on the table. For New York City, that would translate into a September-November mean temperature of 58.8°. On September 18, the MJO was in Phase 8 at an amplitude of 1.561 (RMM). The September 17-adjusted amplitude was 1.201. Based on sensitivity analysis applied to the latest guidance, the implied probability of New York City having a warmer than normal September is approximately 79% and the probability of a monthly mean temperature of 70.0° or above is near 50%.

Averaging can lead to numbers in tenths, hundredths, thousandths of degrees even if the averaged numbers are whole numbers. For example, assume there is a hypothetical 1,000 stations. All but 1 record 50 degree readings. One registers a 51 degree reading. The average is 50.001 degrees, even as no thermometers measure temperature in thousandths of degrees.

Monthly and annual temperature errors within a greater than 95% confidence interval were very small 0.1 to 0.2 degrees C back in 2013. http://static.berkeleyearth.org/memos/robert-rohde-memo.pdf Since then, better ocean measurements have become available and the averaging errors are even smaller. Even at the earlier figures, one could reject the null hypothesis that the global climate had not warmed at a 95% level of confidence.

The issue doesn’t mean measuring sea ice extent or area is not science. The issue concerns limitations of satellite-based measurements and the concept of margins of error. Statistically, when error is considered, measurements within 40,000 km2 are treated as being the same.

More inaccurate information on the climate change denier front. From twitter: One of the biggest flaws in AGW theory are increased heavy rain events. Rain comes from clouds, which form when warm, moist air rises, and cools. This only happens if there's a steep drop in temp with altitude to force the temp to reach the dew point, otherwise, NO clouds form. https://twitter.com/ChrisMartzWX/status/1174553165745786880 The problem with the above claim is that the dew point is not a fixed value. That both the surface and troposphere are warming does not mean that atmospheric temperatures can no longer reach the dew point. What the literature shows is that the warmer atmosphere, which remains capable of cloud formation, holds more moisture. As a result, the frequency of intense precipitation events in parts of the world increase. Such an increased frequency has also shown up in some of the data. https://science2017.globalchange.gov/chapter/7/ Some attribution analyses related to a number of extreme precipitation events can be found at: https://www.worldweatherattribution.org/analysis/rainfall/

On September 18, Arctic sea ice extent increased by 14,600 square kilometers (JAXA) to 3,978,839 square kilometers.

The court transcript related to Mann v. Ball is now available. Key excerpts: There have been at least two extensive periods of delay. Commencing in approximately June 2013, there was a delay of approximately 15 months where nothing was done to move the matter ahead. There was a second extensive period of delay from July 20, 2017 until the filing of the application to dismiss on March 21, 2019, a delay of 20 months. Again, nothing was done during this period to move the matter ahead... The evidence is that the defendant intended to call three witnesses at trial who would have provided evidence going to fair comment and malice. Those witnesses have now died. A fourth witness is no longer able to travel. Thus, in addition to finding that presumption of prejudice has not been rebutted, I also find that there has been actual prejudice to the defendant as a consequence of the delay... Turning to the final factor, I have little hesitation in finding that, on balance, justice requires the action be dismissed. The parties are both in their eighties and Dr. Ball is in poor health. He has had this action hanging over his head like the sword of Damocles for eight years and he will need to wait until January 2021 before the matter proceeds to trial. That is a ten year delay from the original alleged defamatory statement. Other witnesses are also elderly or in poor health. The memories of all parties and witnesses will have faded by the time the matter goes to trial. I find that, because of the delay, it will be difficult, if not impossible, for there to be a fair trial for the defendant. This is a relatively straightforward defamation action and should have been resolved long before now. That it has not been resolved is because the plaintiff has not given it the priority that he should have. In the circumstances, justice requires that the action be dismissed and, accordingly, I do hereby dismiss the action for delay. https://www.bccourts.ca/jdb-txt/sc/19/15/2019BCSC1580.htm In sum, the lawsuit was dismissed on grounds of delay. The delay had nothing to do with Mann's failure to provide materials related to his "hockey stick" analysis and had nothing to do with the substance of climate change. The lawsuit was dismissed on procedural grounds.

After another fall-like day, the coolest night of the season lies ahead courtesy of an air mass that brought several daily record low temperatures to parts of Quebec this morning. Outside New York City, widespread 40s are likely. A few areas where radiational cooling is typically strong could even see readings dip below 40°. However, warmer air will begin to return by Friday. Unseasonable warmth will likely prevail during the upcoming weekend. In Texas, Galveston picked up 6.17" rain from the remains of tropical storm Imelda. That smashed the daily rainfall record of 2.47" from 1979 and was that city's largest daily rainfall since Hurricane Harvey brought 8.64" on August 29, 2017. The two-day figure of 10.65" was the highest since August 28-29, 2017 when 12.43" rain fell from Harvey. The ENSO Region 1+2 anomaly was -1.3°C and the Region 3.4 anomaly was -0.3°C for the week centered around September 11. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.65°C and the ENSO Region 3.4 anomaly has averaged -0.03°C. There remains uncertainty about the ENSO evolution later this fall. Despite the guidance, the strong cooling in Region 1+2 indicates that the prospects for a neutral-cool ENSO during the winter have increased. Such a scenario may be somewhat more likely than not. That outcome could have significant winter season implications. Since 1991 when weekly ENSO region data was available, six years have seen September record 2 or more weeks with -1.0°C or cooler weekly anomalies in Region 1+2: 1996, 1999, 2002, 2007, 2010, and 2017. 5/6 (83%) of those cases went on to feature warm December-February temperature anomalies in the Middle Atlantic and southern New England regions. 2002 had one such week ahead of what would evolve into an El Niño winter. The SOI value was -20.97 today. Today, the preliminary Arctic Oscillation (AO) figure was -1.883. A sharp rebound will very likely commence tomorrow. Since 1950, there have been five prior cases when the AO averaged -0.500 or below in both July and August: 1950, 1958, 1960, 1968, and 2015. The average temperature for September was 69.1° (69.8° after adjusting for ongoing warming) and 58.9° (59.6° adjusted) for September through November in New York City. The 1981-2010 baseline normal figures are 68.0° and 57.5° respectively. The majority of cases saw a warmer than normal September and all cases featured a warmer than normal fall. Among those five cases, 2015 made a transition from predominantly negative AO values to predominantly positive ones during the fall. The combination of the AO's recent increase to the strongest positive values since April and some of the extended range guidance leave open a scenario where the AO is currently in the early stages of evolving to a predominantly positive regime. Such an outcome would also favor a warmer than normal fall and possible warm start to winter in the Middle Atlantic and southern New England regions. For now, this is merely a hypothetical discussion of one potential path toward winter. Many other variables are involved. The only idea that carries weight at this time is that the possible evolution reaffirms the longstanding signal for a warm fall. Therefore, a warmer than normal September and fall appear likely. The potential for autumn 2019 to rank among the 30 warmest cases on record remains on the table. For New York City, that would translate into a September-November mean temperature of 58.8°. The latest EPS weekly data shows widespread warmth across the CONUS during October. On September 17, the MJO was in Phase 8 at an amplitude of 1.200 (RMM). The September 16-adjusted amplitude was 1.078. Based on sensitivity analysis applied to the latest guidance, the implied probability of New York City having a warmer than normal September is approximately 75% and the probability of a monthly mean temperature of 70.0° or above is near 50%.

As the world's attention focuses on climate change, a matter over which the scientific fundamentals are settled, at least one climate change denier has cited a discredited petition allegedly signed by "31,487 scientists." https://twitter.com/tan123/status/1174432569854705669 The 1997 petition comes complete with a non-peer reviewed paper written by Willie Soon, Arthur Robinson, and Noah Robinson, none of whom have backgrounds in climate science or a related field. But there's more. Just as the paper's conclusions were inconsistent with scientific understanding even then, its conclusions were incompatible with basic physics related to greenhouse gas properties (some findings, of which, go back to the 19th century), its signers are far from authentic. The May 1, 1998 issue of The Seattle Times reported: The petition with 15,000 signatures surfaced shortly before the April 22 Earth Day and quickly became music to global warming's critics. They highlighted it in news releases, at congressional hearings, even on the Senate floor... Several environmental groups questioned dozens of the names: "Perry S. Mason" (the fictitious lawyer?), "Michael J. Fox" (the actor?), "Robert C. Byrd" (the senator?), "John C. Grisham" (the lawyer-author?). And then there's the Spice Girl, a k a. Geraldine Halliwell: The petition listed "Dr. Geri Halliwell" and "Dr. Halliwell." https://archive.is/eQIGW The article also noted: Robinson, who acknowledges he has done no direct research into global warming, said the petition includes thousands of people "qualified to speak on this subject" including biochemists, geophysicists and climatologists. Nevertheless, Robinson felt fit to put his name on a "paper" concerning a matter over which he claimed he had "done no direct research." What does that say about Robinson? More broadly, what does it say about the three authors, none of whom have relevant climate science backgrounds to submit peer-reviewed work on climate change, to essentially manufacture a paper, have it posted on Robinson's organization's website in a font and structure that leaves casual readers with the perception that it was published in a journal? What does it say about those peddling the petition, which was documented to have been riddled with fake names?

So far, Galveston has received 5.96" rain today. That easily surpasses the daily record of 2.47", which was set in 1979. It is also Galveston's biggest one-day rainfall total since August 29, 2017 when 8.64" rain associated with Hurricane Harvey fell.

Arctic sea ice extent registered yet another decline on September 17 on JAXA. Arctic sea ice extent stood at 3.964 million square kilometers assuring 2019 the second lowest minimum extent on record. Based on sensitivity analysis applied to the August 31 figure, the bottom 25% value would be 3.916 million square kilometers. https://www.americanwx.com/bb/topic/48618-arctic-sea-ice-extent-area-and-volume/?do=findComment&comment=5308717 The bottom 10%, which was not listed above, would be approximately 3.850 million square kilometers. The latest minimum extent on record is September 30, which was set in 1995 with a minimum extent of 6.018 million square kilomters. During the 2010-18 period, 2 years had minimum extent figures on September 17 and 2018 recorded its minimum extent on September 21.

Brilliant sunshine and crystal clear skies covered the New York City area today. Temperatures across the Middle Atlantic region ranged from the middle 70s to the lower 80s. By Friday, warmer air should push back into the region. Unseasonable warmth could prevail during the upcoming weekend. Meanwhile, both in the Southeast and France, the fierce summer of 2019 raged on. Records in the Southeast included: Apalachicola, FL: 98° (new monthly record); Atlanta: 98°; Crestview, FL: 100° (tied monthly record); Montgomery, AL: 103°. Records in France included: Aubenas: 94° (new monthly record); Brive: 90°; Carcassonne: 91°; Istres: 88°; and Nimes: 98° (new monthly record); and, Orange: 95°. Nimes has now set 4 monthly high temperature marks this year: February: 76°; June: 112° (all-time record); July: 102°; and, September: 98°. In terms of the Arctic, Arctic sea ice extent fell to 3.991 million square kilometers yesterday (JAXA). That assures 2019 of having the second lowest minimum extent on record. Only 2012 had a figure below 4 million square kilometers. In part due to the large-scale absence of sea ice near Alaska, Utqiagvik (formerly Barrow) is on course for what could become that city's warmest September on record. Through yesterday, that city had seen 83 consecutive days with above freezing temperatures, which is 15 days longer than the previous record. The ENSO Region 1+2 anomaly was -1.3°C and the Region 3.4 anomaly was -0.3°C for the week centered around September 11. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.65°C and the ENSO Region 3.4 anomaly has averaged -0.03°C. There remains uncertainty about the ENSO evolution later this fall. Despite the guidance, the strong cooling in Region 1+2 indicates that the prospects for a neutral-cool ENSO during the winter have increased. Such a scenario may be somewhat more likely than not. That outcome could have significant winter season implications. Since 1991 when weekly ENSO region data was available, six years have seen September record 2 or more weeks with -1.0°C or cooler weekly anomalies in Region 1+2: 1996, 1999, 2002, 2007, 2010, and 2017. 5/6 (83%) of those cases went on to feature warm December-February temperature anomalies in the Middle Atlantic and southern New England regions. 2002 had one such week ahead of what would evolve into an El Niño winter. The SOI value was not available today. Today, the preliminary Arctic Oscillation (AO) figure was -1.362. The AO is forecast to return to positive values in a week or less. Since 1950, there have been five prior cases when the AO averaged -0.500 or below in both July and August: 1950, 1958, 1960, 1968, and 2015. The average temperature for September was 69.1° (69.8° after adjusting for ongoing warming) and 58.9° (59.6° adjusted) for September through November in New York City. The 1981-2010 baseline normal figures are 68.0° and 57.5° respectively. The majority of cases saw a warmer than normal September and all cases featured a warmer than normal fall. Among those five cases, 2015 made a transition from predominantly negative AO values to predominantly positive ones during the fall. The combination of the AO's recent increase to the strongest positive values since April and some of the extended range guidance leave open a scenario where the AO is currently in the early stages of evolving to a predominantly positive regime. Such an outcome would also favor a warmer than normal fall and possible warm start to winter in the Middle Atlantic and southern New England regions. For now, this is merely a hypothetical discussion of one potential path toward winter. Many other variables are involved. The only idea that carries weight at this time is that the possible evolution reaffirms the longstanding signal for a warm fall. Therefore, a warmer than normal September and fall appear likely. The potential for autumn 2019 to rank among the 30 warmest cases on record remains on the table. For New York City, that would translate into a September-November mean temperature of 58.8°. The latest EPS weekly data shows widespread warmth across the CONUS during October. On September 16, the MJO was in Phase 8 at an amplitude of 1.075 (RMM). The September 15-adjusted amplitude was 0.905. Based on sensitivity analysis applied to the latest guidance, the implied probability of New York City having a warmer than normal September is approximately 81% and the probability of a monthly mean temperature of 70.0° or above is 52%.

I don't believe many here believed the single model showing an August minimum would verify. Having said this, I suspect we either reached our minimum or will do so in the next 3-5 days. It will be fascinating to see how things play out.

Excerpts: Arctic sea ice freezes each winter after a long summer melt. But surprising warmth during the Arctic winter and spring hampered its build-up — setting the stage for this summer’s dramatic ice loss. The dynamic was especially apparent in the Bering Sea. “From about January to May the sea ice in the Bering Sea just didn’t happen,” says Alice Bradley, a polar scientist at Williams College in Williamstown, Massachusetts. “We haven’t seen that before.” A low-pressure weather system hovered over the sea for much of February, funnelling warm air from the south and pushing the little ice that did manage to form into northern waters. Throughout the spring and summer, Arctic sea ice melted away faster than it usually does in areas such as the Beaufort Sea and the central Arctic Ocean. Ice extent and volume hit record monthly lows in July, and by early August there was no sea ice within 240 kilometres of the Alaskan coast... Between water melting off the ice sheet’s surface and breaking off into icebergs, Greenland likely contributed a little over 1.5 millimetres to global sea-level rise this year, according to polar scientist Xavier Fettweis at the University of Liège in Belgium. When researchers eventually compare the mass lost during this summer’s melt to the mass gained during winter snowfall, Greenland is likely to come out as having lost at least as much in 2019 — or even more — than in the extreme year of 2012. https://www.nature.com/articles/d41586-019-02653-x

Serious scientific debate over climate change has ended. Residual uncertainties persist, but the fundamentals (observed warming; anthropogenic causes; broad increase in heat waves, droughts, and floods, etc.) are widely-agreed. As a result, non-science institutions are increasingly incorporating climate change into their work. One such institution is the International Monetary Fund (IMF). In its April 2019 World Economic Outlook, the IMF observed: There is a need for greater multilateral cooperation to resolve trade conflicts, to address climate change and risks from cybersecurity, and to improve the effectiveness of international taxation... Over the medium term, climate change and political discord in the context of rising inequality are key risks that could lower global potential output, with particularly severe implications for some vulnerable countries... Risks of a somewhat slower-moving nature with serious implications for the medium- and long-term outlook include pervasive effects of climate change and a decline in trust with regard to establishment institutions and political par-ties. The Intergovernmental Panel on Climate Change (IPCC) reported in October 2018 that, at current rates of increase, global warming could reach 1.5°C above preindustrial levels between 2030 and 2052, bringing with it extremes of temperature, precipitation, and drought. Such extremes would have devastating humanitarian effects and inflict severe, persistent output losses across a broad range of economies (Chapter 3 of the October 2017 WEO). The warning from the IPCC comes amid substantial distrust of establishment institutions and mainstream political parties—a distrust often born of rising inequality and entrenched beliefs that existing economic arrangements do not work for all. The accompanying polarization of views and growing appeal of extreme policy plat-forms imperil the medium-term outlook by making it difficult to implement structural reforms for boosting potential output growth and strengthening resilience, including against climate-related risks. Low-income developing countries have also borne the brunt of climate change and potent natural disasters. Lowering the fallout from these events will require adaptation strategies that invest in climate-smart infrastructure, incorporate appropriate technologies and zoning regulations, and deploy well-targeted social safety nets... By adding to migrant flows, climate-related events compound an already-complex situation of refugee flight from conflict areas, often to countries already under severe strain. Box 3.1 of Chapter 3 discussed the price of manufactured low-carbon energy technologies. The IMF recognizes the growing importance of climate change because, among other things, the IMF has member countries that are substantially and adversely impacted by it. For example, earlier this month, the IMF developed a climate change policy assessment for the Federated States of Micronesia. In sum, broad scientific consensus on climate change and its effects are being incorporated outside scientific fields. The IMF provides just one example of how science is beginning to inform the work of such entities.

A warm fall overall appears to be locked in, but the winter outcome is still uncertain. Some recent developments, if things move in the direction suggested, might lead to a warmer than normal winter, but the time-bound uncertainty is too great to have much confidence right now.