Met Office Peddle Extreme Rainfall Lies

By Paul Homewood

The Met Office have now descended to knowingly peddling misinformation:

Extreme rainfall events could be four times as frequent by 2080 compared to 1980s.

For the first time, a high resolution model that captures the detail of convective, or extreme, rainfall events has provided 100 years of data, spanning the past, present and future continuously, to analyse the future risk of rainfall with the intensity that can cause flash flooding.

A version of the Met Office Unified Model, the same that is used for the operational UK weather forecast, has been run 12 times at a resolution of 2.2km (known as k-scale modelling) to give an ensemble of 100-year climate projections.

This is like starting 12 weather forecasts and running them for 100 years, except the researchers are not interested in the weather on a given day but rather how the occurrence of local weather extremes varies year-by-year. By starting the model runs in the past it is also possible to verify the output against observations to assess the model performance.

At this level of detail, it is possible to more accurately assess how convective downpours that can lead to flash flooding will change, for example when the intensity of the rain exceeds 20mm/hour. Thresholds of rainfall intensity like 20mm/hr are used for aspects of planning such as surface water drainage and flood risk.

The research, published in Nature Communications, found that under a high emissions scenario (RCP 8.5) rainfall events in the UK exceeding 20mm/hr could be four times as frequent by 2080 compared to the 1980s. Previous coarser model output (12km) predicted an increase of around two and a half times in the same period.

RCP 8.5 is a pathway where greenhouse gas emissions keep accelerating. This is not inevitable, but a plausible scenario if we do not curb our emissions.

An example of an intense rainfall event with 20mm/hr is London in July 2021, when 40mm of rain fell over three hours at Kew Gardens, flooding the underground and other infrastructure.

https://www.metoffice.gov.uk/about-us/press-office/news/weather-and-climate/2023/new-research-shows-increasing-frequency-of-extreme-rainfall-events

There is no actual evidence provided to prove that extreme rainfall is becoming more frequent, as their computer models say.

Indeed at stations like Oxford, where the Met Office say extreme rainfall will become three times more frequent, the opposite is the case.

https://www.ecad.eu/utils/showindices.php?3v2e59f6q4m5mu3n7rv7k0n0fl

The Met Office is specifically looking at hourly rainfall, which there is very little historical data for. Nevertheless, if this was getting greater the same trend would be seen in daily data; but the actual data shows this is not the case.

Their projections are based on the most extreme GHG scenario, RCP8.5, which they describe as “plausible”. This is false and undeniably implausible. The only reason for the Met Office to use RCP8.5 is for propaganda purposes.

To cap it all, the Met Office offer this as an example:

An example of an intense rainfall event with 20mm/hr is London in July 2021, when 40mm of rain fell over three hours at Kew Gardens, flooding the underground and other infrastructure.

But 40mm of rain in three hours is far from being unprecedented. Maidenhead, for instance, had more than twice as much rain in an hour. Indeed none of the short duration rainfall records have been set since 1989: