As we’ve mentioned, Andrew Dessler and Robert Kopp have been coordinating a scientific peer review of the DOW ‘CWG’ Critique of Climate Science. It is now out.
[Read more…] about Climate Scientists response to DOE reportHurricanes
Critique of Chapter 6 “Extreme Weather” in the DOE review
Guest commentary by Kerry Emanuel
Executive Summary
Chapter 6 of the draft DOE report examines whether global warming exacerbates extreme weather. It rightly notes that because events such as hurricanes are rare, detecting their response to climate change in short and imperfect historical records is extremely difficult—if not impossible. Yet the authors devote most of the remainder of the chapter to attempting just that. By omitting to frame such efforts in the context of theory and models, they commit three fundamental errors: 1) searching for trends where none were predicted, 2) neglecting important variables for which trends were predicted and 3) overlooking—or failing to acknowledge—that some predicted trends are of a magnitude that is not a priori detectable in existing noisy and short data sets. The draft report also overlooks recent literature on climate change effects on weather extremes, and quotes selectively and misleadingly from the most recent report of the Intergovernmental Panel on Climate Change (IPCC). For these reasons, I find much of Chapter 6 to be of questionable utility. There are at least three climate change-induced trends in hurricane-related hazards that were predicted theoretically, simulated by models, and confirmed by observations:
- Hurricanes are producing more rain, causing increased flooding. As water, not wind, is the source of most damage and mortality in hurricanes, this is the most consequential scientific finding.
- The proportion of hurricanes that reach high intensity is increasing.
- Hurricanes are intensifying more rapidly.
There is no robust scientific finding that hurricane frequency is increasing or expected to increase. Thus, much of Chapter 6 of the DOE report is devoted to refuting a hypothesis unsupported by scientific consensus. The short section on tornadoes does not include other more destructive aspects of severe convective storms, such as hail and damaging straight-line winds, and as with the section on hurricanes, omits inferences from theory and models.
[This commentary is also available as a pdf file]
[Read more…] about Critique of Chapter 6 “Extreme Weather” in the DOE reviewWe need NOAA now more than ever
Guest commentary by Robert Hart, Kerry Emanuel, & Lance Bosart
The National Weather Service (NWS) and its parent agency, the National Oceanic and Atmospheric
Administration (NOAA), delivers remarkable value to the taxpayers. This efficiency can be demonstrated by its enormous return on investment. For example, the NWS costs only several dollars per citizen to operate each year, yet results in an estimated 10-100 times larger financial return that includes: improved citizen preparedness, improved transportation efficiency and safety, increased private sector profits, improved disaster prevention and mitigation, and impressive scientific research innovation that is significantly also contributed to by other related federal agencies, the private sector, and the academic research community.
Recent NWS initiatives have even more directly connected weather and ocean observations and forecasts to emergency preparation and public impact. To quote a 2019 study referenced below, “Partnership with the NWS has revolutionized this Emergency Management community from on that reacts to events to one that proactively prepares and stays ahead of the extreme events.” The societal benefits of reasonably predicting the future cannot be understated, and such prediction and resulting benefits were unimaginable only 75 years ago.
Critical taxpayer-funded investments over the past decades have led to greatly improved weather forecast models, observations from the ocean, ground, aircraft, and space, and theoretical understanding through scientific research. These all have had an enormous impact on lives and property. The forecasts and associated critical watches and warnings we see every day on television, the internet, or phone apps could not be possible without NOAA and the NWS. It is estimated that the tax revenue generated from the private sector using NOAA data and services easily pays for the entire cost of the NWS.
Those who remember weather forecasts from the 1970s through 1980s can appreciate these dramatic evolutionary improvements given how inferior those forecasts were compared to today. Going further back, landfalling hurricanes in the first half of that century often came with no warning. If you read newspaper front pages from the mornings of September 7, 1900, or September 21, 1938, you will find there is no mention of the historic and catastrophic events about to unfold only hours later. This would be unthinkable today given the scientific investments we have paid for.
These massive improvements extend beyond hurricane (and also snowstorm) forecasting and preparedness. Tornado warning lead time has also improved markedly during the same time period. Casualty rates from tornadoes have not increased despite a very rapid increase in population. At minimum, hundreds of thousands of people are alive today who would not be without our investments in NOAA and NWS.
The advent of skillful weather forecasting, along with the increased preparedness it allows, remains a landmark achievement of not only this country but of the human race. There are few other fields in the sciences where skillful prediction not only has had immense impact on our society, but is even possible. We should be extraordinarily proud of this achievement.
The current expulsion of primarily younger NOAA employees without cause and with disturbingly short notice is cruel to them personally and professionally. The youngest employees are the future of any organization, government or otherwise, and bring with them unique energy, skills, and ideas. Every government organization should strive to become more efficient, and must be subjected to careful oversight, since taxpayer funding is precious and entrusted to the government by the people. However, the instrument of wise oversight is the scalpel, not the chainsaw. The recent seemingly arbitrary and capricious reductions, notably made without Congressional oversight, are seriously jeopardizing the future of the country and more generally the property and lives of hundreds of millions of tax-paying families who have invested in these truly remarkable achievements over many decades.
References:
“Evolving the National Weather Service to Build a Weather-Ready Nation: Connecting
Observations, Forecasts, and Warnings to Decision-Makers through Impact-Based Decision
Support Services”, Bulletin of the American Meteorological Society, October 2019.
“Using the National Weather Service’s impact-based decision support services to prepare for
extreme winter storms“, Journal of Emergency Management, November/December 2019.
“Impact-Based Decision Support Services (IDSS) and Socioeconomic Impacts of Winter Storms”,
Bulletin of the American Meteorological Society, May 2020.
“Communicating Forecast Uncertainty (CoFU) 2: Replication and Extension of a Survey of the US
Public’s Sources, Perceptions, Uses, and Values for Weather Information.” American
Meteorological Society Policy Program Study, September 2024.
“The Social Value of Hurricane Forecasts”, SSRN Journal, December 2024.
Much ado about acceleration
There has been a lot of commentary about perceived disagreements among climate scientists about whether climate change is (or will soon be) accelerating. As with most punditry, there is less here than it might seem.
[Read more…] about Much ado about acceleration2023 appears to follow an upward trend in the North Atlantic/Caribbean named tropical cyclone count
This year’s (2023) tropical cyclone season in the North Atlantic and Caribbean witnessed a relatively high number of named tropical cyclones: 20. In spite of the current El Niño, which tends to give lower numbers. But it appears to follow a historical trend for named tropical cyclones with an increasing number over time.
The curve presented above is an update of the analysis presented in 2020 and posted here on RealClimate.
[Read more…] about 2023 appears to follow an upward trend in the North Atlantic/Caribbean named tropical cyclone countReferences
- R.E. Benestad, "On tropical cyclone frequency and the warm pool area", Natural Hazards and Earth System Sciences, vol. 9, pp. 635-645, 2009. http://dx.doi.org/10.5194/nhess-9-635-2009
Should the official Atlantic hurricane season be lengthened?
By Jim Kossin, Tim Hall, Mike Mann, and Stefan Rahmstorf
The 2020 Atlantic hurricane season broke a number of records, with the formation of an unprecedented 30 “named storms” (storms that reach wind-speed intensity of at least 18 m/s and are then given an official name). The season also started earlier than normal. In fact, when ranked by their order in the season, the date of formation of every named storm, from Tropical Storm Arthur to Hurricane Iota was substantially earlier than normal (Fig. 1).
2020 vision
No-one needs another litany of all the terrible things that happened this year, but there are three areas relevant to climate science that are worth thinking about:
- What actually happened in climate/weather (and how they can be teased apart). There is a good summary on the BBC radio Discover program covering wildfires, heat waves, Arctic sea ice, the hurricane season, etc. featuring Mike Mann, Nerlie Abram, Sarah Perkins-Kilpatrick, Steve Vavrus and others. In particular, there were also some new analyses of hurricanes (their rapid intensification, slowing, greater precipitation levels etc.), as well as the expanding season for tropical storms that may have climate change components. Yale Climate Connections also has a good summary.
- The accumulation of CMIP6 results. We discussed some aspects of these results extensively – notably the increased spread in Equilibrium Climate Sensitivity, but there is a lot more work to be done on analyzing the still-growing database that will dominate the discussion of climate projections for the next few years. Of particular note will be the need for more sophisticated analyses of these model simulations that take into account observational constraints on ECS and a wider range of future scenarios (beyond just the SSP marker scenarios that were used in CMIP). These issues will be key for the upcoming IPCC 6th Assessment Report and the next National Climate Assessment.
- The intersection of climate and Covid-19.
- The direct connections are clear – massive changes in emissions of aerosols, short-lived polluting gases (like NOx) and CO2 – mainly from reductions in transportation. Initial results demonstrated a clear connection between cleaner air and the pandemic-related restrictions and behavioural changes, but so far the impacts on temperature or other climate variables appear to be too small to detect (Freidlingstein et al, 2020). The impact on global CO2 emissions (LeQuere et al, 2020) has been large (about 10% globally) – but not enough to stop CO2 concentrations from continuing to rise (that would need a reduction of more like 70-80%). Since the impact from CO2 is cumulative this won’t make a big difference in future temperatures unless it is sustained through post-pandemic changes.
- The metaphorical connections are also clear. The instant rise of corona virus-denialism, the propagation of fringe viewpoints from once notable scientists, petitions to undermine mainstream epidemiology, politicized science communications, and the difficulty in matching policy to science (even for politicians who want to just ‘follow the science’), all seem instantly recognizable from a climate change perspective. The notion that climate change was a uniquely wicked problem (because of it’s long term and global nature) has evaporated as quickly as John Ioannidis’ credibility.
I need to take time to note that there has been human toll of Covid-19 on climate science, ranging from the famous (John Houghton) to the families of people you never hear about in the press but whose work underpins the data collection, analysis and understanding we all rely on. This was/is a singular tragedy.
With the La Niña now peaking in the tropical Pacific, we can expect a slightly cooler year in 2021 and perhaps a different character of weather events, though the long-term trends will persist. My hope is that the cracks in the system that 2020 has revealed (across a swathe of issues) can serve as an motivation to improve resilience, equity and planning, across the board. That might well be the most important climate impact of all.
A happier new year to you all.
References
- P.M. Forster, H.I. Forster, M.J. Evans, M.J. Gidden, C.D. Jones, C.A. Keller, R.D. Lamboll, C.L. Quéré, J. Rogelj, D. Rosen, C. Schleussner, T.B. Richardson, C.J. Smith, and S.T. Turnock, "Current and future global climate impacts resulting from COVID-19", Nature Climate Change, vol. 10, pp. 913-919, 2020. http://dx.doi.org/10.1038/s41558-020-0883-0
- C. Le Quéré, R.B. Jackson, M.W. Jones, A.J.P. Smith, S. Abernethy, R.M. Andrew, A.J. De-Gol, D.R. Willis, Y. Shan, J.G. Canadell, P. Friedlingstein, F. Creutzig, and G.P. Peters, "Temporary reduction in daily global CO2 emissions during the COVID-19 forced confinement", Nature Climate Change, vol. 10, pp. 647-653, 2020. http://dx.doi.org/10.1038/s41558-020-0797-x
Absence and Evidence
Guest commentary by Michael Tobis, a retired climate scientist. He is a software developer and science writer living in Ottawa, Ontario.
A recent opinion piece by economist Ross McKitrick in the Financial Post, which attracted considerable attention in Canada, carried the provocative headline “This scientist proved climate change isn’t causing extreme weather – so politicians attacked”.
In fact, the scientist referenced in the headline, Roger Pielke Jr., proved no such thing. He examined some data, but he did not find compelling evidence regarding whether or not human influence is causing or influencing extreme events.
Should such a commonplace failure be broadly promoted as a decisive result that merits public interest?
[Read more…] about Absence and EvidenceDoes a slow AMOC increase the rate of global warming?
Established understanding of the AMOC (sometimes popularly called Gulf Stream System) says that a weaker AMOC leads to a slightly cooler global mean surface temperature due to changes in ocean heat storage. But now, a new paper in Nature claims the opposite and even predicts a phase of rapid global warming. What’s the story?
By Stefan Rahmstorf and Michael Mann
In 1751, the captain of an English slave-trading ship made a historic discovery. While sailing at latitude 25°N in the subtropical North Atlantic Ocean, Captain Henry Ellis lowered a “bucket sea-gauge” down through the warm surface waters into the deep. By means of a long rope and a system of valves, water from various depths could be brought up to the deck, where its temperature was read from a built-in thermometer. To his surprise Captain Ellis found that the deep water was icy cold.
These were the first ever recorded temperature measurements of the deep ocean. And they revealed what is now known to be a fundamental feature of all the world oceans: deep water is always cold. The warm waters of the tropics and subtropics are confined to a thin layer at the surface; the heat of the sun does not slowly warm up the depths as might be expected. Ellis wrote:
“This experiment, which seem’d at first but mere food for curiosity, became in the interim very useful to us. By its means we supplied our cold bath, and cooled our wines or water at pleasure; which is vastly agreeable to us in this burning climate.”
[Read more…] about Does a slow AMOC increase the rate of global warming?
Does global warming make tropical cyclones stronger?
By Stefan Rahmstorf, Kerry Emanuel, Mike Mann and Jim Kossin
Friday marks the official start of the Atlantic hurricane season, which will be watched with interest after last year’s season broke a number of records and e.g. devastated Puerto Rico’s power grid, causing serious problems that persist today. One of us (Mike) is part of a team that has issued a seasonal forecast (see Kozar et al 2012) calling for a roughly average season in terms of overall activity (10 +/- 3 named storms), with tropical Atlantic warmth constituting a favorable factor, but predicted El Nino conditions an unfavorable factor. Meanwhile, the first named storm, Alberto, has gone ahead without waiting for the official start of the season.
In the long term, whether we will see fewer or more tropical cyclones in the Atlantic or in other basins as a consequence of anthropogenic climate change is still much-debated. There is a mounting consensus, however, that we will see more intense hurricanes. So let us revisit the question of whether global warming is leading to more intense tropical storms. Let’s take a step back and look at this issue globally, not just for the Atlantic. [Read more…] about Does global warming make tropical cyclones stronger?