donsutherland1

I would only note that even as the current geoengineering effort started off unintentionally, given the state of today's knowledge, the continuation of it is intentional.

I've seen figures of about 75% should all the ice melt. That's not going to happen anytime soon. Even in the Mid-Pliocene, some ice was retained. An Eocene-type scenario would be a different ballgame. Removing even a modest amount of water could disrupt the water cycle, reducing rock weathering (allowing even more CO2 to pile up in the atmosphere) and producing devastating to catastrophic ecosystem damage. Draining the water could also reduce the oceans' thermal inertia leading to faster warming at each level of CO2. Finally, humanity is already engaged in a colossal geoengineering experiment in which it is pumping CO2 into the atmosphere at an order of magnitude or more above the rapid rise in CO2 that sparked the Paleocene-Eocene Thermal Maximum. Given its reckless ongoing conduct in the face of now full knowledge of the consequences of its geoengineering initiative, my guess is that humanity would ignore potential risks in any new geoengineering effort, probably compounding the damage rather than mitigating it. After all, if they ignore the hazards of their current practices, why would any other geoengineering effort be different?

Yes. The temperature has reached 41 on August 28 and September 8-9.

Investments that would dramatically increase renewables beyond leaving things mainly to the private sector would yield large increases in supply. The cost argument isn't a strong defense. It exists only because the kind of approach to infrastructure that took place in building the nation's highways was not pursued.

The 1922 136° temperature at El Azizia was decertified by the WMO in 2012. The WMO found "five major concerns with the 1922 El Azizia temperature extreme record, specifically 1) potentially problematical instrumentation, 2) a probable new and inexperienced observer at the time of observation, 3) unrepresentative microclimate of the observation site, 4) poor correspondence of the extreme to other locations, and 5) poor comparison to subsequent temperature values recorded at the site." https://journals.ametsoc.org/view/journals/bams/94/2/bams-d-12-00093.1.xml

Global energy demand is rising faster than renewables can scale. Population growth, economic development, and industrial expansion in emerging markets are driving electricity and fuel consumption to record highs. Although solar and wind power generation is growing at double-digit rates, they are adding to energy supply rather than displacing fossil fuels. Political headwinds ranging from a u-turn on climate policy in the United States and retreat from climate ambition in the European Union will likely prolong, if not increase, the excessive consumption of fossil fuels. Unfortunately, at least for the near-term on account of an absence of political will, macroeconomic shocks such as those resulting from the 2008 financial crisis and 2020-21 COVID pandemic may be the only sources of reductions in fossil fuel burning and greenhouse gas emissions. All indications I have seen so far suggest that COP 30 in Brazil will be another farce. There will be empty words, but no binding commitments to even beginning a phase-out of fossil fuels, much less commitments with credible targets and an enforcement mechanism. In sum, the world's leaders have committed to bringing the planet to a new climate epoch. That this will mean sacrificing parts of major cities to the seas or parts of Europe to a chill from the breakdown of the AMOC doesn't deter them. The most relevant question concerns whether they have chosen the Mid-Pliocene or the even hotter Eocene. With approximately 3°C warming likely by 2100 on the present course, the Mid-Pliocene might merely be a stop along the way of an even longer journey into a hotter climate.

The problem is that oil, gas and coal consumption continues to increase, alongside renewables. This persistent growth locks in higher greenhouse gas emissions, undermining climate targets and amplifying extreme weather, sea-level rise, and ecosystem risks. Science has been clear. Scientists have done their job. Human society, at least its political leaders, have decided to continue burn excessive amounts of coal, gas, and oil despite the known consequences of their choice. From Statista: From the IEA: Global coal demand increased to a new all-time high in 2024 of around 8.8 billion tonnes, up 1.5% from 2023, as rising consumption in China, India, Indonesia and other emerging economies more than offset declines in advanced economies in Europe, North America and northeast Asia. However, several of those trends reversed in the first half of 2025 as demand declined in China and India; by contrast, coal use grew by around 10% in the United States. Even so, global coal demand is still set to increase slightly in 2025, followed by a marginal decline in 2026, bringing demand to just below 2024 levels.

The weekend will see a continuation of partly sunny skies with highs mainly in the middle and upper 70s on Saturday. A few of the warmer spots could reach or exceed 80°. Sunday will be somewhat warmer with widespread highs in the lower 80s. Temperatures will top out in the upper 70s to perhaps lower 80s on Monday and Tuesday. September 1-15 remains on track to achieve a solid cool anomaly. Since 2000, there have been nine years that saw a cooler than normal first half of September. Two-thirds of those years went on to record a warmer than normal second half of September. Only two of those years (2017 and 2019) wound up with a monthly mean temperature of 70.0° or above. Overall, for two-thirds of those years, the cool start was sufficiently cool to produce a cooler than normal monthly anomaly. The last year that saw both a cooler than normal first half and second half of September was 2009. Prior to that, it was 2001. The last year to record a cooler than normal first half of September followed by a warmer than normal September was 2024. The latest guidance is continuing to evolve toward a very warm second half of September. As a result, it is plausible that the odds of a warmer than normal September could reach and then exceed 50% as early as tomorrow's guidance. The last September with a cooler than normal first half and a warm overall monthly anomaly was September 2019. The ENSO Region 1+2 anomaly was -0.3°C and the Region 3.4 anomaly was -0.4°C for the week centered around August 27. For the past six weeks, the ENSO Region 1+2 anomaly has averaged +0.33°C and the ENSO Region 3.4 anomaly has averaged -0.32°C. La Niña conditions will likely develop during mid- or late-autumn. The SOI was -1.48 today. The preliminary Arctic Oscillation (AO) was +0.382 today. Based on sensitivity analysis applied to the latest guidance, there is an implied near 51% probability that New York City will have a cooler than normal September (1991-2020 normal). September will likely finish with a mean temperature near 69.1° (0.1° below normal). Supplemental Information: The projected mean would be 1.1° above the 1981-2010 normal monthly value.

The literature is still mixed on the magnitude of its impact. Hopefully, the literature showing more than a minimal impact will ultimately be vindicated. If not, there will be the issue of whether one or more unidentified factors drove the spike. In turn, that would raise questions about whether there are things that are being missed in the climate models, factors that could potentially lead to higher sensitivity. Already, the "hot models" hypothesis has largely been settled. Those models likely have the better handle on climate sensitivity, as their cloud physics have better matched the developments that have now been observed and their scenarios are closer to the paleoclimate data for some past warming events that saw greater climate sensitivity.

Boston and eastern MA largely missed out on that event and it turned to heavy rain for the New York City area for a time. But even with a swath of 10"-20" snows, that event wasn't a high-end KU storm. It was a Category 3 event on the NESIS scale.

Even as a La Niña event is in its formative stages following a neutral-cool/borderline La Niña winter, 2025's global temperatures remain stubbornly warm. The September 1-10 period ranked as the third warmest (ERA-5 dataset). It was 0.10°C warmer than the fourth place 2020.

I don't know of anything that is a very close substitute. The WMO has a site with some of the data, but it is quite complex to use: https://climexp.knmi.nl/start.cgi

A major reason for Russia's rejection of the printing press concerned the Russian Orthodox Church's opposition. The Church felt that the printing press would make it easier to disseminate heresy. It ignored the far greater benefits that could have been realized and were already becoming evident in Western Europe in defense of its much narrower interests.

Tomorrow will be partly sunny with temperatures reaching the middle and upper 70s. The weekend will see a continuation of partly sunny skies with highs mainly in the middle and upper 70s. A few of the warmer spots could reach or exceed 80°. The next round of showers could be Monday. Temperatures will top out in the upper 70s to perhaps lower 80s on Monday and Tuesday. September 1-15 is on track to achieve a solid cool anomaly. Since 2000, there have been nine years that saw a cooler than normal first half of September. Two-thirds of those years went on to record a warmer than normal second half of September. Only two of those years (2017 and 2019) wound up with a monthly mean temperature of 70.0° or above. Overall, for two-thirds of those years, the cool start was sufficiently cool to produce a cooler than normal monthly anomaly. The last year that saw both a cooler than normal first half and second half of September was 2009. Prior to that, it was 2001. The last year to record a cooler than normal first half of September followed by a warmer than normal September was 2024. The ENSO Region 1+2 anomaly was -0.3°C and the Region 3.4 anomaly was -0.4°C for the week centered around August 27. For the past six weeks, the ENSO Region 1+2 anomaly has averaged +0.33°C and the ENSO Region 3.4 anomaly has averaged -0.32°C. La Niña conditions will likely develop during mid- or late-autumn. The SOI was -6.30 today. The preliminary Arctic Oscillation (AO) was +0.370 today. Based on sensitivity analysis applied to the latest guidance, there is an implied near 55% probability that New York City will have a cooler than normal September (1991-2020 normal). September will likely finish with a mean temperature near 68.7° (0.5° below normal). Supplemental Information: The projected mean would be 0.7° above the 1981-2010 normal monthly value.

September 16-30, 2006 had a mean temperature of 66.6, which was slightly above even the 1991-2020 baseline for this period.

China is making the turn toward cleaner energy, as are some of the other countries cited. Better sources of energy exist. The problem is not technological. It's political. Unfortunately, because fossil fuel interests are so entrenched in U.S. society, the United States has chosen to double down on outdated fossil fuel energy. The U.S. will wind up falling behind in terms of energy and possibly a much wider range of fields that utilize energy due to its decision to stick with higher cost, dirtier energy sources. It won't be the first society to bet big on yesterday's technology. During the 15th Century, as the printing press started spreading throughout Europe, Russia chose to reject it. As a result, Russia fell behind in terms of literacy and the creation/dissemination of scientific knowledge for centuries. The end result was slow modernization. Even contemporary Russia is far from a truly modern state. Its economy is largely based on natural resources and little more. It maintains an imperial world view. In short, bad choices have bad consequences.

The new measurement approach is an improvement. La Niñas, particularly weaker ones, would have been masked from a warming of the oceans. They were present, even if not acknowledged.

I'm not arguing and have never argued that site changes didn't play any role in the shift in Denver (initial comment about Denver and afterward). I cited Denver, as it's Colorado's largest city, but the frequency in hot days has increased elsewhere, too. My subsequent comments highlighted that far more than site changes are involved in the big recent increase in 90° and 95° days.

Today, Islip recorded its third consecutive high of 74° and Central Park saw its third consecutive high of 73°. The last time both locations had three consecutive days with the same high simultaneously was during July 6-8, 2000 when both locations had three consecutive highs of 79°. Tomorrow will be briefly warmer with highs in the upper 70s to perhaps lower 80s. A few locations could see a shower or thundershower tomorrow night into Friday as a cold front pushes through. The next round of showers or rainfall could be Monday. September 1-15 is on track to achieve a solid cool anomaly. Since 2000, there have been nine years that saw a cooler than normal first half of September. Two-thirds of those years went on to record a warmer than normal second half of September. Only two of those years (2017 and 2019) wound up with a monthly mean temperature of 70.0° or above. Overall, for two-thirds of those years, the cool start was sufficiently cool to produce a cooler than normal monthly anomaly. The last year that saw both a cooler than normal first half and second half of September was 2009. Prior to that, it was 2001. The last year to record a cooler than normal first half of September followed by a warmer than normal September was 2024. The ENSO Region 1+2 anomaly was -0.3°C and the Region 3.4 anomaly was -0.4°C for the week centered around August 27. For the past six weeks, the ENSO Region 1+2 anomaly has averaged +0.33°C and the ENSO Region 3.4 anomaly has averaged -0.32°C. La Niña conditions will likely develop during mid- or late-autumn. The SOI was -5.70 today. The preliminary Arctic Oscillation (AO) was +0.415 today. Based on sensitivity analysis applied to the latest guidance, there is an implied near 59% probability that New York City will have a cooler than normal September (1991-2020 normal). September will likely finish with a mean temperature near 68.4° (0.8° below normal). Supplemental Information: The projected mean would be 0.4° above the 1981-2010 normal monthly value.

My points are as follows: 1) Denver has seen a dramatic increase in hot days. I used 90° highs as an example. The increase is more than just a result of a location change, even as location changes have an impact, otherwise there wouldn't be warming trends across the entire state. Indeed, I've often noted that adjusted data is superior to raw data, precisely because sites move, environments change, times of observation may change, etc. for climate purposes. 2) The broad idea of a greater frequency of hot days does not negate the existence of localized climates or microclimates. Moreover, that idea applies beyond Denver. For example, Boulder has seen half of years with 50 or more 90° or above days and four of its five years with 20 or more 95° or above highs occur since 2000. For Pueblo, 14 of its 17 years with 80 or more 90° days and 9 of its 10 years with 50 or more 95° days have occurred since 2000. In short, in Colorado's populated areas, the 2000s have seen a disproportionate share of hot days. No other period rivals the 2000s in terms of the frequency of such heat. 3. The old Stapleton Airport does not have a continuous record. The old site was demolished and replaced with Central Park. A new ASOS was installed around 2022 there.

Staptleton Airport was decommissioned, demolished, and replaced by Denver Center Park. The environment is quite different from what it was when record-keeping ended in 1995 at Stapleton Airport. The environment for the new ASOS isn't comparable to what it was at Stapleton Airport. The warming summers since 1995 isn't an artifact of Denver International Airport. It is a statewide phenomenon. 12/15 (80%) of Colorado's summers with a mean temperature of 67.0° or above and all nine of its hottest summers have occurred since 2000. Five of the last six summers (2023 being the exception) have had a mean temperature of 67.0° or above. Statewide maximum temperatures have risen somewhat faster than statewide mean temperatures.

Tomorrow will be variably cloudy with a few showers possible in places. Highs will top out mainly in the upper 60s. Thursday could be briefly warmer with highs in the upper 70s to perhaps lower 80s. A scattered shower or thundershower is possible Thursday night into Friday as a cold front pushes through. September 1-15 is on track to achieve a solid cool anomaly. Since 2000, there have been nine years that saw a cooler than normal first half of September. Two-thirds of those years went on to record a warmer than normal second half of September. Only two of those years (2017 and 2019) wound up with a monthly mean temperature of 70.0° or above. Overall, for two-thirds of those years, the cool start was sufficiently cool to produce a cooler than normal monthly anomaly. The last year that saw both a cooler than normal first half and second half of September was 2009. Prior to that, it was 2001. The last year to record a cooler than normal first half of September followed by a warmer than normal September was 2024. The ENSO Region 1+2 anomaly was -0.3°C and the Region 3.4 anomaly was -0.4°C for the week centered around August 27. For the past six weeks, the ENSO Region 1+2 anomaly has averaged +0.33°C and the ENSO Region 3.4 anomaly has averaged -0.32°C. La Niña conditions will likely develop during mid- or late-autumn. The SOI was -13.78 today. The preliminary Arctic Oscillation (AO) was +0.461 today. Based on sensitivity analysis applied to the latest guidance, there is an implied near 59% probability that New York City will have a cooler than normal September (1991-2020 normal). September will likely finish with a mean temperature near 68.3° (0.9° below normal). Supplemental Information: The projected mean would be 0.3° above the 1981-2010 normal monthly value.

Synoptic scale events can still lead to snowy outcomes even with hostile boundary conditions. The super El Niño winter of 2015-16 is an example. There was a single massive snowstorm that skewed the numbers. There was also a severe Arctic outbreak that sent the mercury in Central Park to -1° on February 14. Much of the rest of the winter was very warm with a lack of snowfall.

Assuming that the SSTs will drive the pattern, he would need big changes from what is forecast for Winter 2025-26 to be similar to that for Winter 2013-14. The core of the warm anomalies would need to shift much farther east. 2013-14 Current Forecast (ECMWF): Current Forecast (CFSv2):

White Plains recorded a low of 53° this morning, its second consecutive day with a low of 53° or below. 2025 has now seen two stretches of at least two consecutive lows of 53° or below through September 9th (August 30-31 and September 8-9). The last time that happened was in 2017 (September 1-2 and September 8-9). Since August 1, White Plains has had 20 days with lows of 59° or below. That is the most since 1994 and tied with 1962 and 1987 for the fourth most. Most Days with Lows < 60° (August 1-September 9): 1. 22, 1964 and 1994 3. 21, 1957 4. 20, 1962, 1987, 2025 7. 19, 1982 8. 18, 1986 9. 17, 1972, 1988, 1997