donsutherland1

The landscape was comprised of savannas, wetlands, and woodlands. Tundra and Taiga were greatly reduced. Greenland's ice sheet was much smaller. The fauna of the period included both familiar and extinct animals. Early ancestors of modern elephants, giraffes, antelopes, along saber-toothed cats and short-faced hyenas were present. Giant ground sloths, camels, and early horses were present in North America Megalodon sharks rule the seas. Whales were evolving into today's forms. Early hominins emerged in Africa. Yes, at the current level of consumption, humanity is on an unsustainable path. The concept of "Earth Overshoot Day" captures a current reality where humanity is consuming more resources each year than what the world can provide. Add pollution (unrestrained greenhouse gas-led geoengineering, plastics/microplastics, a range of chemicals and derivatives) into the mix and that further illustrates unsustainability.

Newark reached 81° today. That was its fifth high of 80° or above during the second half of September and is the most such days since there were seven during September 16-30, 2021.

Additional rain is likely tonight into tomorrow. A storm total 0.50"-1.50" rainfall covering late yesterday through tomorrow is likely in New York City and nearby suburbs. Some locations could see higher amounts in excess of 2.00". The potential for an area of 1.00"-3.00" rainfall exists for parts of Connecticut, Massachusetts, and a secton of southeastern New York State well north and west of New York City. Above normal temperatures will continue through at least the coming weekend. Another round of showers is possible Saturday night into Sunday. In addition, Humberto has developed in the central Atlantic and a second tropical cyclone could develop in the western Atlantic in coming days. The extent of ridging to the north and interaction between the two systems could ultimately determine whether one of these systems poses an eventual threat to a portion of the Southeast or stays out to sea. The potential Fujiwhara interaction would be unusual for the Atlantic basin. Typically, if the stronger system is to the right or east of the weaker one (possibly Invest. 94 as per most of the guidance at present), the stronger system will tend to deflect the weaker one northward and eastward sooner than might otherwise be the case. If both systems are of similar strength, they can rotate counterclockwise around a midpoint roughly between the centers of the two storms as they move along the steering flow. For now, tropics bear watching. The ENSO Region 1+2 anomaly was 0.0°C and the Region 3.4 anomaly was -0.4°C for the week centered around September 17. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.03°C and the ENSO Region 3.4 anomaly has averaged -0.38°C. La Niña conditions will likely develop during mid- or late-autumn. The SOI was +1.43 today. The preliminary Arctic Oscillation (AO) was +1.113 today. Based on sensitivity analysis applied to the latest guidance, there is an implied near 82% probability that New York City will have a warmer than normal September (1991-2020 normal). September will likely finish with a mean temperature near 70.0° (0.8° above normal). Supplemental Information: The projected mean would be 2.0° above the 1981-2010 normal monthly value.

By “unmanageable,” I mean a future marked by significant disruption (economic dislocation, migration, and irreversible environmental/biodiversity loss). These changes will not unfold overnight, but they are already being set in motion. Even a one-meter rise in global sea level, plausible by 2100 and very likely to continue beyond, would reclaim entire neighborhoods of many major coastal cities. Even at one-meter, tens of millions of people would be displaced from major coastal cities. See: https://pmc.ncbi.nlm.nih.gov/articles/PMC8208600/ We don’t have to rely solely on climate models to understand where things are headed under current policy. Paleoclimate evidence is unambiguous. During the mid-Pliocene, when atmospheric CO2 concentrations hovered around 350–450 ppm (levels we have already reached) global temperatures were roughly 3 °C (5.4 °F) warmer than today, and sea level stood at least 10 meters higher than at present. See: https://sciences.ucf.edu/biology/d4lab/wp-content/uploads/sites/23/2018/08/Science-2015-Dutton-.pdf The climate system responds slowly but inexorably to sustained forcing. Ice sheets have not yet equilibrated to today’s CO2 levels, but over centuries to millennia continued melt is inevitable. Research indicates potential hysteresis once a critical threshold is crossed. Under hysteresis, cooling back to current temperatures will not fully restore lost ice. Some modeling places the Greenland Ice Sheet’s critical threshold at roughly 1.7 °C–2.3 °C above pre-industrial temperatures, a range that will likely be surpassed later this century. Warming also amplifies extremes rather than simply shifting the average. Climate change does not “cause” every drought, heatwave, or flood, but it makes them more frequent and more severe, a conclusion supported by a rapidly expanding body of attribution science. See: https://www.worldweatherattribution.org/ Being honest about these well-documented risks is not scaremongering. Communicating evidence-based threats, whether to coastal cities, food and water security, or human health, is a fundamental responsibility of scientists, leaders, and citizens. Describing dangers that the data clearly support is not “spreading fear.” It is providing the information societies need to plan and adapt. That some shrink from the task e.g., as one witnessed at the UN General Assembly, is not an act of courageous leadership. It is an abdication of leadership responsibility and a demonstration of leadership failure. It is a profound display of disregard for the wellbeing of future generations who will have to live with the consequences of bad choices made by those who will evade those very consequences by their having departed the scene well before the tragic returns on their bad policy investments are realized. Given this evidence, the burden of proof no longer lies with scientists who have documented human-induced climate change and its risks. It lies with those who advocate inaction, who must explain how a 3 °C or warmer world relative to pre-industrial temperatures, which is likely by 2100 on the current path, could remain “manageable” despite escalating threats to food and water systems, ongoing ocean acidification, intensifying extreme weather, and one-meter sea-level rise (with more to come beyond 2100). It is their burden to prove at a high confidence level that the laws of physics somehow don't apply in the case of greenhouse gases. Finally, claims that models are unreliable are belied by their track record. Climate models have consistently captured the long-term warming trend with striking accuracy despite the climate system’s complexity. See: https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2019GL085378

As much of the scientific community sees it, the speech openly mocked the First Law of Thermodynamics, the quantum mechanics of molecular absorption, and the established concepts of radiative forcing and planetary energy balance. Trump dismissed these fundamental laws of physics, and the principles derived from them, as a “scam,” a “hoax,” and “the greatest con job ever perpetrated on the world.” History will record this repudiation of evidence as among humanity's worst policy excesses. They will mark this speech as an iconic moment where comfort in falsehood outweighed the responsibility to truth and raw ignorance uprooted scientific understanding. They will see this moment as a vivid symptom of a Great Denial: a period when humanity still had real power to avert a return to mid-Pliocene or worse conditions yet chose to perpetuate the profitability of industries responsible and policy paralysis instead. They will place such rhetoric alongside the campaigns that once denied the link between tobacco and lung cancer or between CFCs and ozone depletion, citing it as evidence that many, including those in positions of authority, preferred tribal loyalty and ideology over science, evidence, and truth. Future generations condemned to endure the realities of a mid-Pliocene climate will condemn those who consigned them to an unmanageable world. No political gimmick will change the physics. There are no instant, magical methods to draw down the accumulated greenhouse gases, reverse the radiative forcing, or reglaciate the ice sheets that have already disappeared, much less the much greater damage that will occur in decades and centuries ahead.

I don't expect that outcome either.

With regard to the EPO, I suspect the current issue is less one about whether it can go positive or negative, but the issue of decreasing variability. In other words, there is greater stickiness for either a positive regime or negative regime during winter and that tendency has increased in recent years. More broadly, this tendency would be consistent with the growing evidence that "stuck patterns" are growing more frequent. And if one looks more closely, the stuck patterns seem to be starting to break in favor of EPO+ values. Here are ratios of the percentage of postive and negative days in January-February vs. percentage of positive and negative days in December. These are currently modest trends.

Convection during neutral ENSO events is more evenly spread out; during La Niña it's farther west (often but not always in the vicinity of the Maritime Continent); during El Niño, it's located in the cental/eastern Pacific. Depending on how the atmosphere and ocean couple, these differences matter. MJO phases in the Maritime Continent often favor warmth in eastern North America. ENSO, of course, is but one variable that shapes seasonal outcomes. Other variables can outweigh it.

2.30”.

Some have speculated toward that end. One article: https://www.space.com/space-exploration/james-webb-space-telescope/is-our-universe-trapped-inside-a-black-hole-this-james-webb-space-telescope-discovery-might-blow-your-mind

Best guess: Probably not this century. This does not apply over geological time frames e.g., long after the human greenhouse gas-emitting supervolcano (hopefully by choice, not circumstances beyond human control e.g., exhaustion of fossil fuel reserves) has gone dormant and CO2 levels drop from the human-induced peak that still lies ahead.

The same physics is involved (conservation of angular momentum) in a rotating system be they celestial bodies or tropical cyclones.

Parts of the region again reached 80° today before clouds moved in. Central Park (80°), Islip, and Newark (81°) all reached at least 80°. A low pressure system will move along a nearly stationary front tomorrow. As a result, rain will develop tonight and continue into Friday. A general 0.50"-1.50" rainfall is likely during this period in New York City and nearby suburbs. Some locations could see higher amounts in excess of 2.00". The potential for an area of 1.00"-3.00" rainfall exists for parts of Connecticut and Massachusetts. Above normal temperatures will continue through at least the coming weekend. In addition, one or two tropical cyclones could develop in the western Atlantic in coming days. The extent of ridging to the north and interaction with a potential second system could ultimately determine whether one of these systems poses an eventual threat to a portion of the Southeast or stays out to sea. The potential Fujiwhara interaction would be unusual for the Atlantic basin. Typically, if the stronger system is to the right or east of the weaker one (possibly Invest. 94 as per most of the guidance at present), the stronger system will tend to deflect the weaker one northward and eastward sooner than might otherwise be the case. If both systems are of similar strength, they can rotate counterclockwise around a midpoint roughly between the centers of the two storms as they move along the steering flow. Then, there's low but not zero probability of a subsequent shift in the steering currents that could turn the storm back toward the coast as depicted on the 9/24 12z ECMWF. For now, the potential development and evolution of pair of tropical cyclones bears watching. The ENSO Region 1+2 anomaly was 0.0°C and the Region 3.4 anomaly was -0.4°C for the week centered around September 17. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.03°C and the ENSO Region 3.4 anomaly has averaged -0.38°C. La Niña conditions will likely develop during mid- or late-autumn. The SOI was +2.62 today. The preliminary Arctic Oscillation (AO) was +0.889 today. Based on sensitivity analysis applied to the latest guidance, there is an implied near 75% probability that New York City will have a warmer than normal September (1991-2020 normal). September will likely finish with a mean temperature near 69.8° (0.6° above normal). Supplemental Information: The projected mean would be 1.8° above the 1981-2010 normal monthly value.

Once one starts getting a large share of hours with above freezing temperatures during snowstorms, the amounts will be capped. So, at some point, even the blockbuster storms probably won't be as big as they have recently been or might be during the early to middle part of the transition. Snowfall extremes may have an asymmetric relationship to averages, at least initially, during the decline. In other words, the extremes e.g., top 1% of values, decline more slowly than the averages. One paper: https://pog.mit.edu/src/ogorman_snowfall_2014.pdf Prior to the decline, extreme values may increase relative to averages, even when averages start to decline. That might have been what happened from the mid-1990s through 2020 in New York City due to the benefit of warmer air holding more water vapor. Such developments are expected in the northern parts of the Northern Hemisphere. Figure 1: The paper from which the chart was taken explains: We find that, for the first half of the 21st century, the 99.9th percentile of daily snowfall, i.e., the largest daily snowfall in 1000 days, increases for large areas of the Northern Hemisphere by 10–20 percentage points until the decade of 2051–2060, while some areas, e.g. in Western Europe, show decreasing extreme percentiles (all percentages are relative to the historical baseline (1851–1920) values, Fig. 1, first column). Towards the end of the century (2091–2100), this trend diverges into sharply decreasing 99.9th percentiles for lower latitudes like Western Europe and parts of North America (up to points), and further increasing percentiles (more than points) in high latitudes. Substantiating these trends, the expected extreme magnitude, i.e., the average of daily snowfall events exceeding the historical 99.9th percentile (for details see the methods, Eq. (2)), increases by 5–10% points until the middle of the century (Fig. 1, second column). This indicates the strengthening of extreme snowfall events. The continued increase until the end of the century to 10–15% points of the baseline level shows that even with rarer extreme events as indicated by decreasing percentiles, the remaining extreme snowfall events are projected to intensify compared to the historical baseline... In contrast to this increase in extreme snowfall statistics, the mean daily snowfall diverges already in the near future. While snow-prone regions in high latitudes exhibit an increase of mean daily snowfall by 20% points until the middle of the century, we observe a sharp decrease for lower latitudes... These trends continue until the end of the century, yielding decreases of up to 80% points in large parts of Europe and parts of North America, while high-latitude regions like Siberia show a similar increase of around at least 50% points. Source: https://www.nature.com/articles/s41598-021-95979-4

Unfortunately, that's true. Humanity failed to make the efforts needed when the requirements were gradual. It is all but certain that the much steeper requirements needed to limit warming won't be pursued. The U.S. has left the playing field so to speak. Europe appears to be retreating.

New York City has had a string of low snowfall winters in the midst of ongoing warming. Arguably, New York City is in the early stages of a structural decline in winter snowfall. Washington, DC has already made a transition to lower snowfall. So, what might it look like if New York City has entered a transition to lower snowfall and how might the evolution unfold afterward? Early-Mid-Transition: Possibly 2020s to Mid-2030s: One can expect larger interannual swings (rising standard deviation in snowfall). Very lean winters will be mixed with some big winters, increasingly defined by fewer bigger events, as warmer air holds more water vapor. The 30-season moving average could increase, at least for a time, before turning downward. Mid-Late-Transition: Possibly Mid-2030s to Mid-2040s: As baseline winters warm further, more storms fall as rain, and snow becomes concentrated into fewer, well-timed cold shots. Interannual variability declines once precipitation falls increasingly as rain. Seasonal snowfall standard deviation flattens and then falls. New Low Snowfall Regime: Possibly Mid-2040s-Mid 2050s The mean is low and the standard deviation is lower than the volatile peak, because snow is infrequent. Big snowstorms don’t vanish outright but become rarer along the coast as rain wins more often. Regional studies for the Eastern U.S. find decreasing annual snowfall but continued potential for occasional high-impact even blockbuster events (fewer in number, increasingly conditional on strong cold air). Select Charts: 30-Season Moving Average Snowfall: The Great Rise during the first quarter of the 21st Century 30-Season Volatility: A Sharp Rise in Volatility: 30-Season Moving Average Snowfall for Biggest Daily Events: Bigger Events Grow Bigger: Percentage of Seasonal Snowfall from 10" or Above Days: Bigger Storms Contributed a Larger Share of Seasonal Snowfall (Mid-1990s-2020): 30-Season Moving Average of the Number of Measurable Snowfall Days: Fewer Days with Measurable Snowfall: In sum, some of the characteristics of an early transition toward lower structural snowfall seem to be present. More time will need to pass before one separates the long-term signal from the noise of internal variability.

Even for the NYC area, using a 0.0°-1.0° warm anomaly over the 1991-2020 baseline isn't a guarantee of a very bad (low) snow season. Looking at all December-March cases that fell within that range at Central Park: Mean seasonal snowfall was 16.9"; median seasonal snowfall was 13.4". In terms of seasons, 13.3% had less than 10" seasonal snowfall but 26.7% had 20" or more. Most common range: 10.0"-19.9" (60.0%). Highest: 38.6", 2020-2021; Lowest: 2.8", 1972-1973. And for 0.5°-1.5° above the 1991-2020 baseline: Mean snowfall: 19.0" Median snowfall: 17.9" Snowfall distribution: 36.4% had 20" or more 18.2% had 30" or more 45.5% had 10.0–19.9" 18.2% had less than 10" Extremes: Snowiest: Winter 2005-2006 with 40.0" Least snowy: Winter 1972-1973 with 2.8" If one were looking at a 40.0° winter, that would signal very bad prospects.

Yes, that's correct. I fixed it..

The preponderance of guidance had it either as a tropical depression or tropical storm. Intensity forecasts this far out aren't very accurate.

With respect to the EPO, the swing from the minimum value during the first half of September to the maximum value (so far) for the second half of September is the fourth largest on record. All of the prior 10 biggest such cases occurred during the evolution toward either La Niña or Neutral-Cool ENSO winters. The composite temperature anomalies for the Neutral-Cool ENSO Winters: The composite temperature anomalies for the La Niña Winters: However, warmth is not a slam dunk for the Northeast/Great Lakes. Winters 1964-65 and 1970-71 were cold in the Northeast, Great Lakes, and Northern Plains. Winters 2007-08 and 2020-2021 were cold in the Central Plains. Finally, the sample size is limited to 10 extreme EPO cases.

The early guidance on Invest 94 now shows a cluster of solutions indicating that the system could be approaching North Carolina in five days. Much can still change, as five day forecasts are subject to large errors. A near miss or out-to-sea solution remains viable.

No. The record is October 10, 2018.

2.0" fell on December 29, 1917.

I recall that event. There was sea smoke rising from the Long Island Sound even as the snow was falling. I doubled the size of an old photo from that storm and highlighted some of the sea smoke.

For Central Park: February 13, 1899: 16.0" snow (High: 11°; Low: 6°) For Newark: December 26, 1872: 16.0" snow (High: 11°; Low: 5°) For Central Park, 18.0" fell on December 26, 1872 with a high of 12° and low of 6°. Data for Measurable Snowfall: Coldest High for Measurable Snowfall: New York City: 8°, February 8, 1895 and December 29, 1917 Newark: 4°, December 29, 1917 Coldest Low for Measurable Snowfall: New York city: -6°, December 29, 1917 Newark: -6°, February 11, 1899 and January 14, 1912