Pielke Jr. Kerry Emanuel’s Latest Slams – Are you interested in that?

Key point⬇️

Originally tweeted by Roger Pielke Jr. (@RogerPielkeJr) above December 2, 2021.

This is the announcement of EurekAlert!

Climate modeling confirms historical records showing increased hurricane activity

New results show that storms in the North Atlantic have increased in frequency over the past 150 years.

Peer-reviewed publications

MASSACHUSETTS INSTITUTE OF TECHNOLOGY

When forecasting how hurricanes might change in the future, it’s a good idea to know something about their past. Judging from historical records dating back to the 1850s, hurricanes in the North Atlantic have become more frequent over the past 150 years.

However, scientists have questioned whether this upward trend is a reflection of reality or simply an artifact of misleading record-keeping. If 19th-century storm trackers had access to 21st-century technology, would they be able to record more storms? This inherent uncertainty has prevented scientists from relying on hurricane records and the models within them for clues about how climate affects hurricanes.

A new MIT study published today in Nature Communications used climate models, rather than storm records, to reconstruct the history of hurricanes and tropical cyclones around the world. Research shows that storms in the North Atlantic have actually increased in frequency over the past 150 years, similar to what the historical record has shown.

In particular, major hurricanes, and hurricanes in general, are more frequent today than in the past. And the invaders appeared more and more powerful, bringing with them more destructive potential.

Curiously, while the North Atlantic has seen an overall increase in hurricane activity, the same trend has not been observed in the rest of the world. The study found that the frequency of tropical cyclones globally has not changed significantly over the past 150 years.

Study author Kerry Emanuel, Cecil and Ida Green’s Professor of Atmospheric Sciences, said: “Evidence points to, as the early historical record suggests, a long-term increase in North Atlantic hurricane activity. Atlantic Ocean, but there were no significant changes in global storm activity. MIT’s Department of Earth, Atmospheric, and Planetary Sciences. “It would certainly change the interpretation of climate impacts on hurricanes – that it was really the regional nature of the climate and that something happened with the North Atlantic that was different from the rest. back of the earth. It can be caused by global warming, which is not necessarily uniform across the globe.”

Chance to meet

The most comprehensive record of tropical cyclones is compiled in a database known as the International Best Recording Archives for Climate Management (IBTrACS). This historical record includes modern measurements from satellites and aircraft dating back to the 1940s. Older records of the database are based on reports from ships and islands that happen to be located in the path of the storm. Previous records date back to 1851, and the database as a whole shows an increase in North Atlantic hurricane activity over the past 150 years.

“No one disagrees that that is what the historical record shows,” says Emanuel. “On the other hand, most sensitive people don’t really trust historical records far away in time.”

Recently, scientists have used statistical methods to identify storms that the historical record may have missed. To do so, they referenced all of the digitally reconstructed shipping lanes in the Atlantic over the past 150 years and mapped them through modern-day hurricane tracks. They then estimate the likelihood that a ship encounters or completely misses the presence of a storm. This analysis shows that a significant number of early hurricanes are likely to be missed in the historical record. Calculating these missed storms, they concluded that it is likely that storm activity has not changed over the past 150 years.

But Emanuel points out that the path of hurricanes in the 19th century may have looked different from the path of today. Furthermore, the scientists may have missed major shipping routes in their analysis, as the older routes have yet to be digitized.

“All we know is, if there is a change (in hurricane activity), it will be undetectable using digitized ship records,” said Emanuel. “So, I think, yes, yes. opportunity to do better, by not using historical data at all.”

Sowing seeds of storm

Instead, he estimates past hurricane activity using dynamic scaling – a technique his team has developed and applied over the past 15 years to study the effects of hurricanes. climate for storms. This technique starts with a rough global climate simulation and embeds in this model a better resolution model that simulates small features such as hurricanes. Combined models are then fed with real-world measurements of atmospheric and ocean conditions. Emanuel then scatters the actual simulation with the storm “seed” and runs the simulation forward in time to see which seeds hatch into major storms.

For the new study, Emanuel embedded a hurricane model in a climate “reanalysis” — a type of climate model that combines observations from the past with climate simulations to generate reconstructions. accurate past weather patterns and climate conditions. He used a specific subset of climate reanalyses that only took into account observations collected from the surface – from ships, for example, which recorded consistent weather conditions and sea surface temperatures. since the 1850s, in contrast to the word satellite, only began to systematically track in the 1970s.

“We chose to use this approach to avoid any artificial bias resulting from the gradual introduction of different observations,” explains Emanuel.

He ran a storm model embedded on three different climate reanalyses, simulating tropical cyclones around the world over the past 150 years. Across all three models, he observed “a marked increase” in North Atlantic hurricane activity.

“There’s been a sizable increase in activity in the Atlantic since the mid-19th century, which I didn’t expect to see,” Emanuel said.

Within the overall increase in hurricane activity, he also observed a “hurricane drought” – the period in the 1970s and 80s when the annual number of hurricanes momentarily dropped. The pause in storm activity can also be seen in historical records, and Emanuel’s team suggests one cause: sulfate aerosols, which are a byproduct of fossil fuel combustion, likely. causes a cascade of climate effects that cool the North Atlantic and temporarily suppress storm formation.

Emanuel notes: “The general trend over the past 150 years has been increased hurricane activity, interrupted by this drought storm. “And at this point, we’re more confident about why there are drought storms than why there’s been a sustained, long-term increase in activity starting in the 19th century. That still remains. is a mystery, and it raises questions about how global warming might affect future Atlantic hurricanes.”

This research was supported in part by the National Science Foundation.

###

Written by Jennifer Chu, MIT News Office

JOURNEYS

Nature Communications

ARTICLE TITLE

Atlantic tropical cyclones downsize from climate reanalyses showing increased activity over the past 150 years

Disclaimer: AAAS and EurekAlert! is not responsible for the accuracy of