Page 4 of 4

Re: Deluge Thread 2018

Unread postPosted: Mon 09 Jul 2018, 20:48:57
by dohboi

Re: Deluge Thread 2018

Unread postPosted: Tue 31 Jul 2018, 21:40:00
by dohboi
Another one to add to the long file labeled: "faster (more intense...) than expected consequences of AGW":

Australia facing extremely intense rain storms.
Landmark study shows how heavy, short rain storms are intensifying more rapidly than would be expected with global warming. Jul 30, 2018. Newcastle University ... 120245.htm

The team of international scientists, led by Dr Selma Guerreiro at the School of Engineering, Newcastle University, UK, has for the first time found increases in short, intense rain storms over Australia over the past 50 years.
The storms are substantially larger than would be expected under climate change.
Published today in Nature Climate Change, the study shows that in Australia:
1, Extreme daily rainfall events are increasing as would be expected from the levels of regional or global warming that we are experiencing
2. the amount of water falling in hourly rain storms (for example thunderstorms) is increasing at a rate 2 to 3 times higher than expected, with the most extreme events showing the largest increases.
3. large increase has implications for the frequency and severity of flash floods, particularly if the rate stays the same into the future.

Professor Seth Westra, co-author from the University of Adelaide, Australia, said:
“These changes are well above what engineers currently take into account when determining Australia’s flood planning levels or designing stormwater management and flood defence infrastructure.
“If we keep seeing this rate of change, we risk committing future generations to levels of flood risk that are unacceptable by today’s standards.”

Re: Deluge Thread 2018

Unread postPosted: Thu 23 Aug 2018, 11:07:13
by jedrider

Re: Deluge Thread 2018

Unread postPosted: Wed 05 Sep 2018, 23:40:38
by dohboi ... d-drought/

North Korea hit by devastating floods after unprecedented drought

Re: Deluge Thread 2018

Unread postPosted: Fri 07 Sep 2018, 23:55:12
by Keith_McClary
Fifty-six million years ago, the Pyrenees were being formed, and their foothills were traversed by small isolated channels in a floodplain where they deposited highly fertile alluvium, promoting the development of vegetation whose roots would anchor the soil. Leaving the Pyrenean piedmont, these small rivers then headed west into the Atlantic, which was then only about 30 kilometres away.

"With global warming, the landscape changed completely. The channel-forming floods, which occur on average every two to three years and whose flow we have been able to measure, went up to 14 times greater than before when the climate was cooler," explains Sébastien Castelltort. During the PETM, rivers constantly changed course, they no longer adapted to increased discharge by incising their bed, but instead, they widened, sometimes dramatically, from 15 to 160 meters wide in the most extreme case. Instead of being trapped in the floodplains, the alluvium was transferred directly toward the ocean, and the vegetation seemed to disappear. The landscape turned into arid extensive gravel plains, crossed by ephemeral and torrential rivers.

Co-author Professor Rich Pancost from Bristol's School of Earth Sciences, explained how these findings agree with a range of geological and chemical features of the Palaeocene-Eocene global warming.

He said: "This warming event is associated with major changes in how soil and sediment were eroded and moved around the landscape.

"In many places, river systems that had been transporting silt or sand became associated with fist-sized rocks or even boulders; and more sediment was transported to and buried in coastal margins. In some locations, the rate of sediment accumulation increased by a factor of ten. But at the same time, there is also evidence that these systems became more arid.

"Our climate simulations reconcile this for many locations, showing an increase in aridity with fewer but more intense rainfall events. Those events were likely responsible for increased energy in these systems, moving around more material and larger objects. Ultimately it flushed more sediment to the ocean, causing eutrophication, blooms of algae and in some cases hypoxia."