donsutherland1

The literature cites increasing Arctic solar insolation, often from fluctuations in the earth’s orbit, as one of the natural mechanisms that kicks off the initial warming. As temperatures rise, stored carbon is unlocked and the atmospheric concentration of carbon dioxide increases. In turn, the increased atmospheric concentration of carbon dioxide promotes additional warming. Given the physical properties of carbon dioxide, it should make no difference how the stored carbon dioxide is released. The impact should be the same if the physical properties of CO2 are understood correctly. The observed ongoing warming is consistent with what one would expect when atmospheric carbon dioxide increases. I said nothing about feedbacks, as one is dealing with the much larger issue of forcings. Additional feedbacks, some of which are non-linear and some of which are still poorly understood, influence how much warming actually takes place. Nevertheless, the general scientific conclusion concerning the role increasing anthropogenic greenhouse gas forcing has played in driving ongoing warming is a very high confidence matter in science. The confidence level will likely be 99%-100% when the IPCC publishes its next assessment (an increase from the current 95% figure). I strongly disagree that the objectivity of climate scientists has been corrupted by “money, fame, power and egos.” If anything, it is the movement that rejects AGW that faces that problem. It offers no credible empirically-supported alternative to AGW. It increasingly evades the research and publication route by which scientific knowledge is built/expanded/revised, likely because it is trapped by the limits imposed by science itself and it cannot bear subjecting its lack of alternative to rigorous scrutiny. Absent a concrete scientific basis for its positions, it increasingly displays motivated reasoning consistent with its sources of funding (often fossil fuel-related interests).

The “lag” issue has been explained numerous times: Step 1: Begin the release of CO2 — initial warming kicked off by natural processes was the mechanism Step 2: Amplify the initial rise in temperatures — increasing atmospheric CO2 amplified the initial rise in temperatures. Since the Industrial Revolution and especially during the 20th century and beyond, humanity has substituted itself for the natural mechanism in releasing CO2. Atmospheric CO2 is increasing and ongoing warming is the result. This is the expected climate response. The only way one can claim that humanity has no role in driving current developments would if CO2’s physical properties were somehow altered only when human activities released it. Under such a claim, the rising concentration would be minor to irrelevant. That’s not the case.

Morning thoughts... Today will be mainly cloudy with perhaps a few widely scattered showers. Temperatures will likely reach the middle to perhaps upper 70s across the region. Likely high temperatures around the region include: New York City (Central Park): 76° Newark: 78° Philadelphia: 79° The temperature will likely remain above normal through the remainder of the month. Cooler air will arrive to start October.

During the summer and early fall (early spring in the Southern Hemisphere), numerous daily and monthly high temperature records, including some all-time high temperature records, along with monthly mean temperature records were broken. A number of locations experienced their hottest summer on record. July 2020 was Phoenix’s hottest month on record. August 2020 was even hotter. Summer 2020 was, by far, Phoenix’s hottest summer on record. Parts of South America and Southern Africa are currently experiencing their most intense early spring heat on record. Research demonstrates that climate change has led to an increase in summertime high temperature records, which are tied to prolonged heat waves, by more than a factor of ten. There is approximately an 80% probability that the new records have been made possible by anthropogenic climate change. Further increases in such records are likely in coming decades as the world’s climate continues to warm. https://www.researchgate.net/publication/234114398_Global_increase_in_record-breaking_monthly-mean_temperatures

Under partly to mostly cloudy skies, temperatures rose mainly into the middle 70s across the region. In parts of South America, a historic early spring heatwave toppled monthly records. Some monthly records included: Asuncion, Paraguay: 108° Corrientes, Argentina: 109° Foz Do Iguacu, Brazil: 102° Pozo Hondo, Paraguay: 114° ***New all-time national high temperature record*** Meanwhile, in parts of Europe, early-season snows blanketed even the lower elevations of the Alps. Temperatures will likely remain at generally above normal levels for the remainder of September. A cool shot is likely during the opening week of October, but warmer readings could return during the following week. Phoenix has an implied 95% probability of recording just its 13th September on record with a mean temperature of 90° or above. The most recent such occurrence was 2018 with a mean temperature of 91.8°. Phoenix will very likely record its hottest June-September period on record with a four-month mean temperature of near 95.4°. That would exceed the previous June-August record of 95.1°, which was set in 2013 and tied in 2015. The existing record is 93.9°, which was set in 2011. October could be wetter than September in and around the New York City area. Since 1950, 10 of the 12 (83%) of the La Niña cases that followed an El Niño winter saw October receive more precipitation than September, including 7 of the 8 (88%) cases since 1980. October 1954 and October 1998 were the exceptions. The largest increase in precipitation occurred in 2005. September 2005 saw just 0.48" precipitation in New York City. October 2005 received 16.73" precipitation. The ENSO Region 1+2 anomaly was -0.4°C and the Region 3.4 anomaly was -0.8°C for the week centered around September 16. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.93°C and the ENSO Region 3.4 anomaly has averaged -0.68°C. La Niña conditions have developed and will likely prevail through the remainder of autumn. The SOI was +16.11. Today, the preliminary Arctic Oscillation (AO) figure was +0.683. On September 25, the MJO was in Phase 5 at an amplitude of 1.350 (RMM). The September 24-adjusted amplitude was 1.442. Since 1990, there have been 11 La Niña events, 6 of which followed an El Niño winter. 10/11 (91%) case saw warmer than normal September. All 6 following an El Niño winter were warmer than normal. September mean temperatures for New York City for those cases were: 11 cases: 69.9°; Subset of 6 cases: 70.8°; Entire 1990-2019 period: 69.0°. The September mean temperature for all La Niña and neutral-cool cases following an El Niño winter (1950-2019: n=13) was 69.9°. Since 1950, there have been five cases where a La Niña developed during June-July-August or afterward following an El Niño winter. 4/5 (80%) of those cases saw a predominant EPO+/AO+ winter pattern. The most recent such case was 2016-17. 9/10 (90%) of the La Niña winters that followed an El Niño winter featured a predominantly positive EPO. Based on sensitivity analysis applied to the latest guidance, there is an implied 85% probability that New York City will have a warmer than normal September. September will likely finish with a mean temperature near 68.6°.

Abstract: Extreme weather events in Asia have been occurring with increasing frequency as the globe warms in response to rising concentrations of greenhouse gases. Many of these events arise from weather regimes that persist over a region for days or even weeks, resulting in disruptive heatwaves, droughts, flooding, snowfalls, and cold spells. We investigate changes in the persistence of large-scale weather systems through a pattern-recognition approach based on daily 500 hPa geopotential height anomalies over the Asian continent. By tracking consecutive days that the atmosphere resides in a particular pattern, we identify long-duration events (LDEs), defined as lasting longer than three days, and measure their frequency of occurrence over time in each pattern. We find that regimes featuring positive height anomalies in high latitudes are occurring more often as the Arctic warms faster than mid-latitudes, both in the recent past and in model projections for the twenty-first century assuming unabated greenhouse gas emissions. The increased dominance of these patterns corresponds to a higher likelihood of LDEs, suggesting that persistent weather conditions will occur more frequently. By mapping observed temperature and precipitation extremes onto each atmospheric regime, we gain insight into the types of disruptive weather events that will become more prevalent as particular patterns become more common. https://www.nature.com/articles/s41598-020-71945-4

Morning thoughts... At 8:45 am, a shrinking area of moderate to heavy rain that had brought 0.66" rain to Wilmington was headed northward toward Allentown. Much of the rest of the region was cloudy with a few widely scattered light showers. Today will be mainly cloudy with perhaps a few additional showers. The sun could begin to break through the clouds during the afternoon. Temperatures will likely reach the lower to perhaps middle 70s across the region. Likely high temperatures around the region include: New York City (Central Park): 74° Newark: 75° Philadelphia: 75° The temperature will likely remain above normal through the remainder of the month.

@blizzard1024Tree rings at some locations had seemingly become a less reliable indicator of temperature. More recent research suggests that light (dimming) may have been responsible. https://phys.org/news/2014-05-arctic-tree-ring-divergence-problem.html

I’m not sure if the below paper has been posted here, but it allows for comparisons of Arctic sea ice volume during the first half of the 20th century, including the 1920-40 Arctic warming, and the rapid declines in volume today. The paper is: Arctic Sea Ice Volume Variability over 1901–2010: A Model-Based Reconstruction https://journals.ametsoc.org/jcli/article/32/15/4731/343909/Arctic-Sea-Ice-Volume-Variability-over-1901-2010-A

If the use of proxy data is the “weakest link,” how would you go about trying to compare today’s temperatures with those during the rest of the Holocene?

Tomorrow will be mainly cloudy with perhaps a few showers and a little cooler than today. In general, temperatures will likely remain at generally above normal levels for the remainder of September. A cool shot is possible in the opening week of October, but warmer readings could return during the following week. Phoenix has an implied 90% probability of recording just its 13th September on record with a mean temperature of 90° or above. The most recent such occurrence was 2018 with a mean temperature of 91.8°. Phoenix will very likely record its hottest June-September period on record with a four-month mean temperature of near 95.3°. That would exceed the previous June-August record of 95.1°, which was set in 2013 and tied in 2015. The existing record is 93.9°, which was set in 2011. The ENSO Region 1+2 anomaly was -0.4°C and the Region 3.4 anomaly was -0.8°C for the week centered around September 16. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.93°C and the ENSO Region 3.4 anomaly has averaged -0.68°C. La Niña conditions have developed and will likely prevail through the remainder of autumn. The SOI was +16.88. Today, the preliminary Arctic Oscillation (AO) figure was +0.613. On September 24, the MJO was in Phase 5 at an amplitude of 1.436 (RMM). The September 23-adjusted amplitude was 1.370. Since 1990, there have been 11 La Niña events, 6 of which followed an El Niño winter. 10/11 (91%) case saw warmer than normal September. All 6 following an El Niño winter were warmer than normal. September mean temperatures for New York City for those cases were: 11 cases: 69.9°; Subset of 6 cases: 70.8°; Entire 1990-2019 period: 69.0°. The September mean temperature for all La Niña and neutral-cool cases following an El Niño winter (1950-2019: n=13) was 69.9°. Since 1950, there have been five cases where a La Niña developed during June-July-August or afterward following an El Niño winter. 4/5 (80%) of those cases saw a predominant EPO+/AO+ winter pattern. The most recent such case was 2016-17. 9/10 (90%) of the La Niña winters that followed an El Niño winter featured a predominantly positive EPO. Based on sensitivity analysis applied to the latest guidance, there is an implied 79% probability that New York City will have a warmer than normal September. September will likely finish with a mean temperature near 68.6°.

The American Meteorological Society (AMS) just published the state of the climate report for 2019. Excerpts: All major greenhouse gases released into Earth’s atmosphere reached new record high concentrations in 2019. The annual global average carbon dioxide concentration at Earth’s surface was 409.8 ± 0.1 ppm, an increase of 2.5 ± 0.1 ppm over 2018, and the highest in the modern instrumental record and in ice core records dating back 800 000 years. Greenhouse gases, along with several halogenated gases, have contributed to a 45% increase in net forcing compared to 1990. Carbon dioxide is responsible for nearly two-thirds of this increase. A weak El Niño early in the year transitioned to ENSO-neutral conditions by mid-year, yet the annual global surface temperature across land and ocean surfaces was still among the three highest on record. July became the hottest month in records dating to the mid- to late-1800s. Each decade since 1980 is warmer than its preceding decade, with 2010–19 being around 0.2°C warmer than 2000–09. In 2019, there were a record high number of extreme warm days (temperatures above the 90th percentile) over global land surfaces. There were also a low number of extreme cool days (temperatures below the 10th percentile) compared to the last 70 years, but there were more cool days compared to the average of just the past decade. A new indicator introduced this year to the report—marine heat waves—indicates that the number of strong marine heatwaves surpassed the number of more moderate marine heat waves for the sixth consecutive year. Lake temperatures increased on average across the globe in 2019; observed Northern Hemisphere lakes were covered in ice seven days fewer than the 1981–2010 average, accord- ing to phenological records. Over land, the growing season was an average of eight days longer than the 2000–10 average in the Northern Hemisphere. In colder regions, alpine glaciers around the world continued to lose mass for the 32nd consecutive year, while record high permafrost temperatures were observed at many observing sites across the high northern latitudes. The complete report can be found here: https://www.ametsoc.org/ams/index.cfm/publications/bulletin-of-the-american-meteorological-society-bams/state-of-the-climate/

Climate Proxies: Some resources: Introduction to Climate Science: Paleoclimate: https://open.oregonstate.education/climatechange/chapter/paleoclimate/ What is Paleoclimatology? https://www.ncei.noaa.gov/news/what-is-paleoclimatology Data: Paleoclimatology data: https://www.ncdc.noaa.gov/data-access/paleoclimatology-data

Abrupt as in taking place in a matter of decades rather than the far longer geological timeframes such changes have typical (not always) occurred. Actually, I probably should have used a somewhat different term, as abrupt can infer an unexpected development when the warming is consistent with the latest understanding of climate change. Also, there’s no need to dismiss the work of paleoclimatologists who have pieced together climate records from various proxies. The proxies offer a reasonably consistent picture. They provide a lot of insight. The alternative is to pretend that what wasn’t recorded is unknown and unknowable. That’s not a scientific approach.

No climate scientist has published a paper that argues that the climate was "in almost complete stasis" since 1000 CE. Climate has always been dynamic due to changes in natural forcings, not to mention internal variability. There have been periods where it has been relatively more stable than at other periods. The big issue concerns the abrupt and sharp warming that commenced since the mid-20th century, predominantly on account of anthropogenic greenhouse gas emissions. That warming has occurred despite little change in solar irradiance and a long-term decline in summer solar insolation in the Arctic. The change in the atmospheric concentration of CO2 and the warming that has occurred in mere decades is remarkable, as such changes have typically (not always) occurred over geological timeframes, not decades.

Phoenix recorded its hottest summer (June 1-August 31) on record. Anthropogentic climate change has been driving an observed global warming. Within that global climate context, Phoenix has experienced both a warming of its summers and a lengthening of its summer-like temperatures. If one looks back at the climate model projections for the RCP 4.5 scenario, one finds that the climate model projections run in 2005 were very accurate in depicting what the summer 2011-2020 period would be like. Looking ahead, the summer 2021-2030 period will likely be even warmer under the RCP 4.5 scenario. Phoenix: Summer 2011-20 High Temperatures and Projected 2021-30 High Temperatures:

Morning thoughts... Today will be partly sunny and warm. The temperature will likely top out mainly in the upper 70s with a few lower 80s across the region. Likely high temperatures around the region include: New York City (Central Park): 78° Newark: 80° Philadelphia: 78° The temperature will likely remain above normal through the remainder of the month. Yesterday was Las Vegas' 157th consecutive day with no measurable precipitation. That is the longest such stretch on record for that city.

Those claims are aimed at dismissing climate scientists to circumvent the absence of scientific evidence to dismiss AGW. While we’re discussing independence or perceived independence of researchers, it should be noted that Lindzen cited above had been receiving funding from coal interests (Peabody Energy). https://www.theguardian.com/environment/2016/jun/13/peabody-energy-coal-mining-climate-change-denial-funding

A review of the scientific literature on climate change and wildfires: https://news.sciencebrief.org/wildfires-sep2020-update/

New Record Low Northern Hemisphere Temperature: From the World Meteorological Organization: WMO has recognized a temperature of -69.6°C (-93.3°F) at an automatic weather station in Greenland on 22 December 1991 as the lowest ever recorded in the Northern Hemisphere. The temperature record was uncovered after nearly 30 years by “climate detectives” with the WMO Archive of Weather and Climate Extremes. It eclipses the value of -67.8°C recorded at the Russian sites of Verkhoyanksk (February 1892) and Oimekon (January 1933). The world’s coldest temperature record, of -89.2°C (-128.6°F) on 21 July 1983, is held by the high-altitude Vostok weather station in Antarctica. https://wmo.asu.edu/new-coldest-northern-hemispheric-temperature The related paper: https://rmets.onlinelibrary.wiley.com/doi/10.1002/qj.3901

CNN reported: California's Creek Fire is not only the largest single wildfire in the state known for huge and destructive blazes, it spawned two rare firenados a day after the fire started earlier this month. One firenado -- short for fire tornado -- was rated an EF-2, with winds up to 125 miles per hour. The other had winds of up to 100 miles per hour and was rated an EF-1. They wreaked havoc across the rugged area, the result of "unprecedented fire behavior," government forecasters said Thursday. https://www.cnn.com/2020/09/24/us/california-fire-tornado-creek-fire/index.html

As the issue about climate models has arisen on numerous occasions, here’s a good introduction from University of Arizona paleoclimatologist Jessica Tierney featuring NASA Goddard Institute for Space Studies Director Gavin Schmidt: In terms of model performance, here’s a recent paper that evaluates the performance of climate models: https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2019GL085378

Temperatures rose in the 70s across the region today. Tomorrow will likely be somewhat warmer with more sunshine than today. In the Rockies, Denver reached 91° today. That surpassed the previous daily record of 89°, which was set in 1992. It was also Denver's 75th 90° or warmer day. The previous annual record was 73 days in 2012. Temperatures will likely remain at generally above normal levels for the remainder of September. A cool shot is possible to open October. Phoenix has an implied 91% probability of recording just its 13th September on record with a mean temperature of 90° or above. The most recent such occurrence was 2018 with a mean temperature of 91.8°. Phoenix will very likely record its hottest June-September period on record with a four-month mean temperature of 95.3°-95.5°. That would exceed the previous June-August record of 95.1°, which was set in 2013 and tied in 2015. The existing record is 93.9°, which was set in 2011. The ENSO Region 1+2 anomaly was -0.4°C and the Region 3.4 anomaly was -0.8°C for the week centered around September 16. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.93°C and the ENSO Region 3.4 anomaly has averaged -0.68°C. La Niña conditions have developed and will likely prevail through the remainder of autumn. The SOI was +14.26. Today, the preliminary Arctic Oscillation (AO) figure was +0.211. On September 23, the MJO was in Phase 5 at an amplitude of 1.368 (RMM). The September 22-adjusted amplitude was 1.168. Since 1990, there have been 11 La Niña events, 6 of which followed an El Niño winter. 10/11 (91%) case saw warmer than normal September. All 6 following an El Niño winter were warmer than normal. September mean temperatures for New York City for those cases were: 11 cases: 69.9°; Subset of 6 cases: 70.8°; Entire 1990-2019 period: 69.0°. The September mean temperature for all La Niña and neutral-cool cases following an El Niño winter (1950-2019: n=13) was 69.9°. Since 1950, there have been five cases where a La Niña developed during June-July-August or afterward following an El Niño winter. 4/5 (80%) of those cases saw a predominant EPO+/AO+ winter pattern. The most recent such case was 2016-17. 9/10 (90%) of the La Niña winters that followed an El Niño winter featured a predominantly positive EPO. Based on sensitivity analysis applied to the latest guidance, there is an implied 70% probability that New York City will have a warmer than normal September. September will likely finish with a mean temperature near 68.4°.

Denver reached 90 degrees today for a record 75th time this year. The 91-degree temperature beat the previous daily record of 89 degrees, which was set in 1992.

A newly published paper revealed new evidence of a slowing of the Atlantic Meridional Overturning Circulation (AMOC) in response anthropogenic warming. The paper can found here.