Archives par mot-clé : Cyclones

Little evidence of changes in extreme weather trends

by P. Homewood, July 27, 2022 in NotaLotofPeopleKnowThat


New IPCC attribution statistics are distorting observational evidence

London, 27 July – A new paper from the Global Warming Policy Foundation finds that the IPCC’s recent shift in methodology has led to misleading claims about changes in weather extremes.

The review, from physicist Dr Ralph Alexander, finds that IPCC claims that many of these weather extremes are increasing significantly are largely unsupported by observational evidence.

Ralph Alexander: Extreme Weather: The IPCC’s Changing Tune (pdf)

According to Dr Alexander:
“On almost every kind of extreme weather, with the possible exemption of heatwaves, the evidence for significant changes is scant. But the latest IPCC report has introduced novel ‘attribution’ statistics and now insists that things are getting worse. It’s yet another case of scientists trying to scare the public into compliance.”

Dr Alexander’s paper looks at:
– droughts
– floods
– hurricanes
– tornadoes
– wildfires
– hot and cold extremes
– coral bleaching.

He concludes that:
“The mistaken belief that weather extremes are worsening because of climate change is more a perception, fostered by media coverage, than reality. The IPCC’s new statistical method is playing an unworthy part in bringing this sorry state of affairs to pass.”

GWPF invited the Royal Society and the Met Office to review this paper, and to submit a response to be published as an appendix to it. No reply was received.

Declining tropical cyclone frequency under global warming

by S. Chand et al., Jun 27, 2022 in Nature


Abstract

Assessing the role of anthropogenic warming from temporally inhomogeneous historical data in the presence of large natural variability is difficult and has caused conflicting conclusions on detection and attribution of tropical cyclone (TC) trends. Here, using a reconstructed long-term proxy of annual TC numbers together with high-resolution climate model experiments, we show robust declining trends in the annual number of TCs at global and regional scales during the twentieth century. The Twentieth Century Reanalysis (20CR) dataset is used for reconstruction because, compared with other reanalyses, it assimilates only sea-level pressure fields rather than utilize all available observations in the troposphere, making it less sensitive to temporal inhomogeneities in the observations. It can also capture TC signatures from the pre-satellite era reasonably well. The declining trends found are consistent with the twentieth century weakening of the Hadley and Walker circulations, which make conditions for TC formation less favourable.

Study: Tropical Cyclone Frequency Decreasing As Earth Mildly Warms

by S. Chand et al., Jun 28, 2022 in ClimateChangeDispatch


Assessing the role of anthropogenic warming from temporally inhomogeneous historical data in the presence of large natural variability is difficult and has caused conflicting conclusions on the detection and attribution of tropical cyclone (TC) trends. [bold, links added]

Here, using a reconstructed long-term proxy of annual TC numbers together with high-resolution climate model experiments, we show robust declining trends in the annual number of TCs at global and regional scales during the twentieth century.

The Twentieth Century Reanalysis (20CR) dataset is used for reconstruction because, compared with other reanalyses, it assimilates only sea-level pressure fields rather than utilizing all available observations in the troposphere, making it less sensitive to temporal inhomogeneities in the observations.

It can also capture TC signatures from the pre-satellite era reasonably well.

The declining trends found are consistent with the twentieth-century weakening of the Hadley and Walker circulations, which make conditions for TC formation less favorable.

Human activities are estimated to have caused ~1.0 °C of global warming above pre-industrial levels, with most of the warming occurring since the mid-twentieth century1.

CO2 Cyclone Doomsday Flat Out Refuted: 170 Years “Absolutely No Trend” In Hurricane Intensity/Frequency

by P. Gosselin, May, 22, 2021 in NoTricksZone


The latest comes from statistics expert, Zoe Phin, who looks at the alarmists’ claim that increasing CO2 emissions are leading to more frequent and intense Atlantic hurricanes.

Alarmist claims cost nothing, and so easily made. Zoe Phin looks at whether the hurricane alarmist claim holds up.

Frequency

First Zoe looked at the (HURDAT2) data to find out if the first of the two claims (increasing frequency) is true. At first glance it would appear so.

But Zoe asks if the method of measuring the frequency really is sensible and if it maybe weren’t better to measure the amount of time the Atlantic spends in hurricane mode? To find out, Zoe plotted the hurricane hours data and the 10-year moving average:

Source: Zoe Phin.

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