[Storm Daniel was a Mediterranean cyclone or hurricane (a
"medicane") that struck Greece, Bulgaria, Libya, Egypt and Turkey,
killing thousands. Climatologists are struggling to understand whether
this is a harbinger of North Africas future.]
[[link removed]]

WAS THE FREAK ‘MEDICANE’ STORM THAT DEVASTATED LIBYA A GLIMPSE OF
NORTH AFRICA’S FUTURE?  
[[link removed]]


 

Mike Rogerson, Belkasem Alkaryani and Mahjoor Lone
September 21, 2023
The Conversation
[[link removed]]


*
[[link removed]]
*
[[link removed]]
*
*
[[link removed]]

_ Storm Daniel was a Mediterranean cyclone or hurricane (a
"medicane") that struck Greece, Bulgaria, Libya, Egypt and Turkey,
killing thousands. Climatologists are struggling to understand whether
this is a harbinger of North Africa's future. _

Catastrophic flooding in Libya has caused thousands of deaths,

 

Storm Daniel landed on the Libyan coastal town of Toukrah in the early
hours of September 10 and started moving east. Soon the wind was
rising and heavy rain falling, forcing people to stay indoors. By
afternoon the rain was clearly out of the ordinary.

Albaydah city on the coast would receive 80% of its annual rain before
midnight, according to records from a local weather station that we
have accessed. In less than 24 hours, thousands of people were dead,
hundreds of thousands were missing, and towns and villages across
Jebel Akhdar (the Green Mountain) in north-eastern Libya resembled a
Hollywood disaster movie.

Storm Daniel was a Mediterranean cyclone or hurricane (a so-called
medicane) which struck Greece, Bulgaria, Libya, Egypt and Turkey over
the course of a week. Medicanes are not rare. Such large storms happen
in this part of the world every few years. But Daniel has proved to be
the deadliest.

At the time of writing, the World Health Organization estimates
[[link removed]]
that at least 3,958 people have died across Libya as a result of the
floods, with more than 9,000 people still missing.

Daniel was not an exceptionally big storm though. The medicane with
the highest wind speeds was medicane Ianos in September 2020, which
killed around four people and caused more than €224 million (£193
million) of damage
[[link removed]].
So what made Storm Daniel different?

Less frequent, but stronger

Like tropical cyclones, medicanes form in hot conditions at the end of
summer. Most medicanes form to the west of the islands of Corsica and
Sardinia. As they tend to strike the same regions each time, the
people living in the western Mediterranean, southern Italy and western
Greece, have built structures to deal with these storms and the
occasional downpours they bring.

Daniel formed relatively far to the east and struck north-eastern
Libya, which is rare. Dozens of people were killed in communities
across Cyrenaica, the eastern portion of the country.

In the mountain gorge above the city of Derna, two dams failed
[[link removed]]
in the middle of the night. Thousands of people, most of whom were
asleep, are thought to have perished when the wave of water and debris
swept down to the coast, destroying a quarter of the city.

Since medicanes are formed in part by excess heat, events like this
are highly sensitive to climate change. A rapid attribution study
suggested greenhouse gas emissions made Daniel 50 times more likely
[[link removed]].

Despite this, the sixth assessment report
[[link removed]] from the UN Intergovernmental
Panel on Climate Change (IPCC) concluded that medicanes are becoming
less frequent but larger. Storm Daniel suggests where medicanes form
and make landfall might be more important than their frequency and
size.

So does Libya need to brace itself for more of these events in the
future than it has in the past, even if they affect the western
Mediterranean less often?

Clues from the past

An important clue might lie deep underground, inside caves within
north-eastern Libya. Although the caves are often dry today, they
contain stalagmites which formed when rain passed through the soil,
into the rock and dripped into the cave below thousands of years ago.

These rock formations attest to times in the past when this region was
considerably wetter. The caves in Libya – and in Tunisia and Egypt
too – form these stalagmites when the global climate is warm.

These bygone warm periods are not quite the same as the warm periods
IPCC forecasts suggest modern climate change will usher in. But the
way a hot world, a relatively ice-free Europe and North America and a
wet northern Africa have regularly coincided in the past is striking.
Striking and difficult to understand.

That’s because the experiments that suggest medicanes will become
less frequent as the climate warms belong to a pattern described by
IPCC climate assessments, in which wet parts of the world are expected
to get wetter and dry parts drier. So it is hard to understand why
stalagmites tell us warmer periods in the past involved wetter
conditions across the northern margin of the Sahara – one of the
driest regions on Earth.

Fortunately, scientists can learn more from the way stalagmites
sometimes grow imperfectly, leaving tiny blobs of water trapped
between the crystals.

The stalagmite we recovered from Susah Cave
[[link removed]]
on the outskirts of Libya’s Susah city, which was severely damaged
in the storm, had quite a lot of water in it from wet periods dating
to 70,000 to 30,000 years ago. The oxygen and hydrogen isotopes in
this water are suggestive of rain drawn from the Mediterranean. This
could indicate more medicanes were hitting the Libyan coast then.

Our finding that more rain was falling above Susah Cave during warm
periods suggests we should get more storms hitting eastern Libya as
the climate warms. This is not quite what the IPCC forecasts, with
their prediction of fewer but larger storms, show.

But storm strength is measured in wind speed, not rainfall. The caves
could well be recording an important detail of past storminess which
we’re not yet able to forecast.

Are stalagmites warning us that North Africa must prepare for future
medicanes shifting further east? Our ongoing research
[[link removed]] aims to answer that
question.

The pattern of ancient desert margins receiving more rain during warm
periods despite the “dry gets drier” pattern of global climate
models is not unique to northern Africa but found around the world.
Over millions of years, globally warm periods almost always correspond
with smaller deserts in Africa, Arabia, Asia and Australia.

This “dryland climate paradox” is important to unravel.
Understanding the differences between climate models and studies of
ancient rain will be key to navigating the future as safely as
possible.

[Imagine weekly climate newsletter]
 

_DON’T HAVE TIME TO READ ABOUT CLIMATE CHANGE AS MUCH AS YOU’D
LIKE?_
_Get a weekly roundup in your inbox instead.
[[link removed]]
Every Wednesday, The Conversation’s environment editor writes
Imagine, a short email that goes a little deeper into just one climate
issue. Join the 20,000+ readers who’ve subscribed so far.
[[link removed]]_[The
Conversation]

Mike Rogerson
[[link removed]], Senior
Lecturer in Earth System Science, _Northumbria University, Newcastle
[[link removed]]_;
Belkasem Alkaryani
[[link removed]],
Lecturer in Geology, _University of Tobruk
[[link removed]]_,
and Mahjoor Lone
[[link removed]],
Postdoctoral Research Associate in Palaeoclimatology, _Northumbria
University, Newcastle
[[link removed]]_

This article is republished from The Conversation
[[link removed]] under a Creative Commons license. Read
the original article
[[link removed]].

* Libya
[[link removed]]
* Global warming
[[link removed]]
* floods
[[link removed]]

*
[[link removed]]
*
[[link removed]]
*
*
[[link removed]]

 

 

 

INTERPRET THE WORLD AND CHANGE IT

 

 

Submit via web
[[link removed]]

Submit via email
Frequently asked questions
[[link removed]]

Manage subscription
[[link removed]]

Visit xxxxxx.org
[[link removed]]

Twitter [[link removed]]

Facebook [[link removed]]

 




[link removed]

To unsubscribe, click the following link:
[link removed]