donsutherland1

His paper did not reach conclusions “regardless to which set of numbers was used.” As a result, the paper has largely withstood the test of time. Today, at least in the scientific field, it is considered among the breakthrough works that have informed the evolution of understanding of climate change. If you can point me to peer-reviewed research that finds his basic conclusion was wrong, please share it. The studies that followed largely upheld the paper with some revisions for the 1400-1500 period. The most important part concluding that the warming during the late 20th century (which has now been exceeded in the early 21st century) was greater than anything that had occurred during the prior 600 years was reaffirmed in the follow-up research. Today, there is no serious debate that the current global temperatures are unprecedented during the current 1,000 years. Within a few decades or less, they will likely be the warmest of the entire Holocene Interglacial Period. Moreover, the warming is more abrupt and rapid than anything that took place in the Holocene. Taking potshots at modeling to evade the largely sound conclusions of Dr. Mann’s paper is the “strawman.” Moreover, the modeling from the 1970s and 1980s, even as it was fairly rudimentary at that time, has proved quite accurate.

Tomorrow and Friday will feature much warmer than normal conditions. The temperature will generally reach the middle and upper 80s across the region. A few hot spots could reach 90°. A deep trough will move from Canada toward the Great Lakes Region and into the Northern Plains starting this weekend. This trough will likely provide a period of somewhat cooler weather. Most of the colder air will stay west of the Appalachians. That trough may persist until near or just after mid-month. Nevertheless, the first half of September will likely wind up somewhat warmer than normal. The ENSO Region 1+2 anomaly was -0.6°C and the Region 3.4 anomaly was -0.7°C for the week centered around August 26. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -1.02°C and the ENSO Region 3.4 anomaly has averaged -0.63°C. Neutral-cool conditions will likely evolve into La Niña conditions during the fall. The SOI was +20.15. Today, the preliminary Arctic Oscillation (AO) figure was +0.502. On September 1, the MJO was in Phase 3 at an amplitude of 1.421 (RMM). The August 31-adjusted amplitude was 1.655. 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°. Overall, the evolution of ENSO, along with the observed ongoing monthly warming (1.6°/decade in NYC and 1.5°/decade in the Northeast Region during September 1990-2019), favors a warmer than normal September. 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. Finally, on September 1, Arctic sea ice extent was 3.895 million square kilometers (JAXA). Based on the August 31 figure, minimum Arctic sea ice extent will most likely finish somewhere from 3.645 million to 3.695 million square kilometers in September. The highest 25% bound is 3.742 million square kilometers. The lowest 25% bound is 3.581 million square kilometers. 2020 is the second consecutive year with a minimum extent figure below 4.000 million square kilometers and the third such year on record.

Mann created his landmark temperature chart from multiple lines of proxy data and the instrument record.

Much of Mann’s construction, including the “blade” illustrating the anomalous late 20th century warming were reaffirmed in subsequent research. https://ral.ucar.edu/projects/rc4a/millennium/refs/Wahl_ClimChange2007.pdf

Article on Phoenix’s historic summer by The Washington Post’s Capital Weather Gang: https://www.washingtonpost.com/weather/2020/09/01/phoenix-hottest-summer

He is a scientist: http://www.met.psu.edu/people/mem45 His work has also been cited more than 38,000 times.

Here is the extended information that includes the 30-year periods ending in 1930 and 1940 for Phoenix. Average Summer Temperatures (30-Year Moving Average):

I have confidence in the large and growing body of peer-reviewed research on the matter. Further, there is no alternative explanation that even begins to account for the observed warming that has occurred since 1950. Models that rely solely on natural forcings cannot reliably reproduce the warming. Those that include anthropogenic greenhouse gases do very well.

Initially, one could make a compelling argument that Phoenix’s warming was being driven by growing urbanization. But that has changed. During the 1990-2020 period, the 30-year moving average for summer temperatures rose 2.7° at Phoenix but 1.4° at Tombstone (current population 1,330). However, if one excludes the 1990s, the increases were 1.5° and 1.0° respectively. Since 2010, Tombstone actually saw greater warming than Phoenix, even as its population fell slightly from 1,382. In addition, as with Phoenix, a disproportionate share of Tombstone’s 10 warmest summers have occurred since 2000. In fact, 9 of Tombstone’s 10 warmest summers have occurred since 2010. In sum, the recent data is consistent with what the overwhelming body of scientific research shows overall: Most of the recent warming is related to anthropogenic climate change, not location-specific factors such as the Urban Heat Island (UHI) effect. Not surprisingly, IPCC is considering raising the level of confidence about the role of anthropogenic factors leading to most of the recent warming to 99%-100% for the Sixth Assessment Report that will be published next year.

Urbanization was cited as one of three factors by the National Weather Service. Climate change was another. Moreover, the idea that urbanization is responsible for the outcome was addressed by NWS Phoenix which stated, "The record summer heat wasn't just in Phoenix, or solely due to Urbanization. A large chunk of the SW saw exceptional heat and all-time records. Some other locations w/ all-time summer records: Lost Dutchman SP, Carefree, Tombstone, Tucson, & Nogales."

Morning thoughts... At 8:20, a large area of light rain with some embedded heavier showers was moving eastward across southern and central New York State and Connecticut. The rain was north of New York City. Another area of showers was located in eastern Pennsylvania. Today will be mostly cloudy with some showers. Thundershowers are possible this evening and tonight as a warm front moves northward. Temperatures will will reach the upper 70s and lower 80s across the region. Likely high temperatures around the region include: New York City (Central Park): 80° Newark: 83° Philadelphia: 85° Tomorrow and Friday will be noticeably warmer days. Afterward, a deep trough in Canada will move toward the Great Lakes Region and provide a period of somewhat cooler weather. That trough may persist until near mid-September.

Tomorrow will be partly to mostly cloudy with possible showers and perhaps a thundershower. Total rainfall amounts will generally be 0.25" or less. Afterward, temperatures will likely return to above normal levels for several days. However, a deep trough will move from Canada toward the Great Lakes Region and into the Northern Plains starting this weekend. This trough will likely provide a period of somewhat cooler weather. Most of the colder air will stay west of the Appalachians. That trough may persist until near or just after mid-month. Nevertheless, the first half of September will likely wind up somewhat warmer than normal and September, as a whole, will likely finish warmer than normal (generally 1°-3° above normal). The ENSO Region 1+2 anomaly was -0.6°C and the Region 3.4 anomaly was -0.7°C for the week centered around August 26. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -1.02°C and the ENSO Region 3.4 anomaly has averaged -0.63°C. Neutral-cool conditions will likely evolve into La Niña conditions during the fall. The SOI was +18.44. Today, the preliminary Arctic Oscillation (AO) figure was +0.464. On August 31, the MJO was in Phase 3 at an amplitude of 1.654 (RMM). The August 30-adjusted amplitude was 1.626. 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°. Overall, the evolution of ENSO, along with the observed ongoing monthly warming (1.6°/decade in NYC and 1.5°/decade in the Northeast Region during September 1990-2019), favors a warmer than normal September. 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. Finally, on August 31, Arctic sea ice extent was 3.943 million square kilometers (JAXA). Based on the August 31 figure, minimum Arctic sea ice extent will most likely finish somewhere from 3.645 million to 3.695 million square kilometers in September. The highest 25% bound is 3.742 million square kilometers. The lowest 25% bound is 3.581 million square kilometers. 2020 is the second consecutive year with a minimum extent figure below 4.000 million square kilometers and the third such year on record.

Scientists are able to tell that anthropogenic activities have led to most of the increase in atmospheric concentration of CO2. The carbon atoms in fossil fuels are “light.” The increase in atmospheric CO2 has been occurring while the ratio of “light” - to - “heavy” carbon has been increasing, as well. Thus scientists are confident about the reason the atmospheric concentration of CO2 is rising.

Another tweet from the Phoenix office of the National Weather Service: https://twitter.com/NWSPhoenix/status/1300795549499756544?s=20

When the IOD is positive, the MJO is often in more favorable phases. However, long-term changes in sea surface temperatures are promoting an increased tendency for the MJO to reside in the Maritime Continent. Here's a paper @bluewave posted on this topic: https://www.nature.com/articles/s41586-019-1764-4

Morning thoughts... Overnight, showers brought 0.12" rain to New York City and Newark. Those showers are now departing from the region. The remainder of today will be partly to mostly cloudy. There could still be another shower. Temperatures will be in the 70s across much of the area except near or just above 80° in southern New Jersey southward. Likely high temperatures around the region include: New York City (Central Park): 76° Newark: 79° Philadelphia: 81° Temperatures will likely return to above normal levels near or just after mid-week. Afterward, a deep trough in Canada will move toward the Great Lakes Region and provide a period of somewhat cooler weather. That trough may persist until near mid-September. Phoenix, which just experienced its hottest summer, by far, could see a new period of excessive heat develop late this week.

From the NWS Phoenix forecast office:

Anthropogenic greenhouse gases are the dominant variable driving the changes.

The IOD state at this time of year doesn’t seem to have much influence. During the winter, and IOD- has often seen an increased tendency for the MJO to reside in the Maritime Continent phases (Phases 4 and 5).

Because the empirical evidence is strong. It assumes basic understanding that statistics measure things. Statistics are not abstractions unto themselves. The changes taking place are leading to warmer, drier conditions in general. The incidence of extreme heat, including this August’s record-breaking heat in parts of California and Arizona have increased the frequency of conditions that are conducive for wildfires.

You misunderstand the differences of climate (fixed point in time) and climate change (delta between two states of the climate) and the role that measurements play in providing insight into both. An analogy is useful: Average heart rate is a statistic. Average heart rate has no power over one’s health and has never caused one a heart attack or other serious heart issue. The underlying assumption, if one applies the implicit arguments concerning climate change to this measure, would be that whether one’s heart rate is rapidly slowing or becoming highly irregular would be irrelevant. In other words, there’s nothing to see. That would be dangerously naive. Large and dramatic changes could well indicate that a person is suffering a heart issue which, if not addressed, could pose a mortal threat. The same holds true for climate statistics. The change over time has meaning. And, because there is a relationship between many of the climate variables (higher temperatures-incidence of extreme heat, changes in global distribution of temperatures and the jet stream, greater warmth-greater capacity of the atmosphere to hold moisture, etc.) the overall changes taking place pose risks ranging from heat waves, drought, rising sea levels, etc. None of these changes are trivial.

If the idea that Phoenix’s climate will resemble that of Baghdad is reasonably accurate, then there could be some nights with lows at or above 100 (Phoenix’s lows are higher than those in Baghdad) and highs in the lower and middle 120s during periods of extreme heat.

New York City's Central Park finished with a monthly mean temperature of 76.9° for August. Its summer mean temperature was also 76.9°, which tied summers 1949, 1983, and 1993 for the fourth warmest summer on record. Tomorrow will be mainly cloudy with showers and some periods of rain possible. Rainfall amounts will likely come to 0.25" or less for much of the region. Temperatures will be in the middle and upper 70s. Beyond midweek, temperatures will likely return to above normal levels. Afterward, a deep trough in Canada will move toward the Great Lakes Region and provide a period of cooler weather. Most of the colder air will stay west of the Appalachians. That trough may persist until near or just after mid-September. Nevertheless, the first half of September will likely wind up somewhat warmer than normal and September, as a whole, will likely finish warmer than normal (generally 1°-3° above normal). Parts of the Northeast and also Southwest recorded their warmest summer on record. At New York City's LaGuardia Airport, the summer mean temperature was 79.5°, which surpassed the prior record of 79.2° from 2010. Phoenix had, by far, its warmest summer on record. Phoenix concluded with a summer mean temperature of 96.7°. That smashed the previous record of 95.1°, which was set in summer 2013 and tied in summer 2015. August 2020 was surpassed July's record for the warmest month on record with a mean temperature of 99.0°. To date, Phoenix has smashed its record for most days with high temperatures of 110° or above (50), 115° or above (13), and low temperatures of 90° or above (28). More on Phoenix's historic summer can be found here: The ENSO Region 1+2 anomaly was -0.6°C and the Region 3.4 anomaly was -0.7°C for the week centered around August 26. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -1.02°C and the ENSO Region 3.4 anomaly has averaged -0.63°C. Neutral-cool conditions will likely evolve into La Niña conditions during the fall. The SOI was +21.36. Today, the preliminary Arctic Oscillation (AO) figure was -0.535. Daily MJO data remains unavailable. 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°. Overall, the evolution of ENSO, along with the observed ongoing monthly warming (1.6°/decade in NYC and 1.5°/decade in the Northeast Region during September 1990-2019), favors a warmer than normal September. 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. Finally, on August 30, Arctic sea ice extent was 3.995 million square kilometers (JAXA). 2020 will be the second consecutive year with a minimum figure below 4.000 million square kilometers and third time on record. The highest 25% bound is 3.768 million square kilometers. The lowest 25% bound is 3.589 million square kilometers.

Phoenix concluded, by far, its hottest summer on record. During June-August 2020, Phoenix had a mean temperature of 96.7°. That smashed the old record of 95.1°, which was set in 2013 and tied in 2015. Table 1: Summer 2020 Average Temperatures Since 2009, every summer has ranked among the 20 warmest summers on record. In addition, 2015, 2016, 2019 and 2020 have ranked among the 10 warmest summers. Table 2: 20 Warmest Summers Monthly Mean Temperatures: June: 92.0° (21st warmest June on record) July: 98.9° (warmest July on record; old record: 98.3°, 2009) August: 99.1° (warmest August on record; old record: 98.3°, 2011) July 2020 set a new monthly mean temperature. August 2020 surpassed that record. Just 3 (15%) of the 20 warmest months were recorded prior to 2000. 17 (85%) of the warmest months occurred 2000 or later and 10 (50%) of the warmest months occurred 2010 or later. There were three cases where both July and August ranked among the 20 warmest months: 2007, 2019 and 2020. Table 3: 20 Warmest Months Table 4: Record High Minimum Temperatures Table 5: Record High Maximum Temperatures Select Monthly Heat Thresholds: Highs 110° or above: 22 days, August 2020 (old record: 19 days, July 2020; prior old record: 18 days, June 1974) Highs 115° or above: 7 days, August 2020 (tied record set in June 1974) Lows: 90° or above: 16 days, July 2020 (old record: 11 days, July 2006); August 2020 had 12 such days. Select Summer Heat Thresholds: Highs 110° or above: 48 days (old record: 31 days, 2007 and 2011) Highs 115° or above: 13 days (old record: 7 days, 1974) Lows: 90° or above: 28 days (old record: 15 days, 2003 and 2013) Climate Change: Anthropogenic climate change is driving a warming of Phoenix's summers. The warming has accelerated in recent decades. The observed global warming since the 1950s is unequivocal with anthropogenic greenhouse gas emissions being the dominant driver of that warming (IPCC Climate Change Synthesis Report 2014). The warming is a global phenomenon with 98% of the world having experienced its warmest 51 years during the current 2,000 years (Neukom, et al. 2019). Recent research suggests that Phoenix's climate will resemble that of Baghdad by 2050 (Bastin, et al. 2019). During the summer, Baghdad typically receives no rainfall. Baghdad's average high temperatures (Weather Atlas 2002-2020) during the summer months are: June: 105.8° July: 111.2° August: 109.4° Summer Average High Temperature: 108.8° Until summer 2020, the highest mean summer maximum temperature was 107.0°, which was set in 1978 and tied in 1989. The highest monthly summer maximum temperature was 109.8°, which was set in July 1989 and tied in July 2020. August 2020 surpassed that record with an average high temperature of 110.7°. As recently as 2000, Phoenix's average low temperature during the summer was 79.8°. Since 1999, Phoenix has had no summer with an average low temperature below 80.0°. Prior to 2020, the highest average monthly minimum temperature was 87.5°, which was set in August 2011. July 2020 had an average minimum temperature of 88.0°. Based on the above research findings, summer 2020 provides a glimpse of what a typical Phoenix summer will be like by 2050. Table 6: Average Summer Temperatures (30-Year Moving Average) Climate change is also resulting in an increase in the frequency of days on which the low temperature stays at or above 90° and the high temperature reaches 100° or above, 110° or above, and 115° or above. Table 7: Average Annual Days at Set Thresholds (30-Year Moving Average) According to the Fourth National Climate Assessment, Phoenix saw 60 to nearly 100 100° days per year at the 5th and 95th percentiles. Under the RCP 4.5 scenario, those figures are projected to increase to 110-141 days per year during the 2070-2099 period. During the 1950-1999 period, 9 (18%) of years saw the number of 100° days fall within the projected RCP 4.5 interval (U.S. Global Change Research Program, 2017). From 2000-2019, 11 (55%) of years fell within that interval. 2020 is all but certain to become the 12th case since 2000 to meet that higher interval. Moreover, through August 31, the 30-year moving average is just above 110 days per year. During the summer, 48 days saw high temperatures 110° or above. The previous summer record was 31 days, which was set in 2007 and tied in 2011. During 2020, there have been 50 such days vs. the prior record of 33 days, which was set in 2011. There were also 28 days on which the minimum temperature was 90° or above, which eclipsed the previous record of 15, which was set in 2003 and tied in 2013. In addition, the number of very hot (high temperature of 110° or above) and super hot (high temperature of 115° or above) days has been increasing as a share of the increasing number of 100° days. For the 30-year period ending in 1980, 12.6% of 100° days had high temperatures of 110° or above and 1.0% saw temperatures reach 115° or above. For the 30-year period ending in 2000, those figures increased to 15.7% and 1.7% respectively. For the period ending in 2020 (through August 31), those figures increased further to 18.8% and 2.0% respectively. Overall, the frequency and intensity of compound summertime hot extremes (events that combine daytime and nighttime heat where such temperatures are above their 90th percentile for their calendar) has been increasing especially in geographic locations that include the U.S. Southwest (Wang 2020). The increase in forcing associated with anthropogenic greenhouse gases is the dominant driver of this outcome. (Wang 2020). During summer 2020, 15 record high minimum temperatures were tied or broken in Phoenix and 14 record high maximum temperatures were tied or broken. On 7 days, both record high minimum and maximum temperatures were tied or broken. Summary: Summer 2020 saw Phoenix record its highest summer temperature on record. It also saw Phoenix experience its two hottest months on record. In addition, Phoenix easily surpassed records for the most days on which the temperature reached 110° or above and on which minimum temperature was 90° or higher. Anthropogenic climate change, which has turned hot patterns hotter and increased pattern persistence, is largely responsible for this exceptional warmth. Based on the latest research, the extreme heat of summer 2020 will likely become the "new normal" by 2050. Updates: September 1-7: https://www.americanwx.com/bb/topic/53697-phoenix-records-its-hottest-summer-on-record/?do=findComment&comment=5650331 Summer High Temperatures: Climate Model Projections and Actual Outcomes: https://www.americanwx.com/bb/topic/53697-phoenix-records-its-hottest-summer-on-record/?do=findComment&comment=5661632 Phoenix Records a 90° Mean Temperature for September: https://www.americanwx.com/bb/topic/53697-phoenix-records-its-hottest-summer-on-record/?do=findComment&comment=5664607 Phoenix Experiences its Hottest Week in October: https://www.americanwx.com/bb/topic/53697-phoenix-records-its-hottest-summer-on-record/?do=findComment&comment=5668129 Phoenix Sets New Annual Record for 100° Days: https://www.americanwx.com/bb/topic/53697-phoenix-records-its-hottest-summer-on-record/?do=findComment&comment=5672012 A Very Warm October Concludes in Phoenix: https://www.americanwx.com/bb/topic/53697-phoenix-records-its-hottest-summer-on-record/?do=findComment&comment=5684211 Phoenix Experiences its Warmest 5-Day November Period on Record: https://www.americanwx.com/bb/topic/53697-phoenix-records-its-hottest-summer-on-record/?do=findComment&comment=5687553 Phoenix Experiences Latest 90° Days on Record: https://www.americanwx.com/bb/topic/53697-phoenix-records-its-hottest-summer-on-record/?do=findComment&comment=5698629

A healthier diet and other lifestyle changes, independent of anything to do with climate change, would likely reduce comorbidities among the American population, expanding with life spans and the quality of life.