Climate Change/Mass Extinction Megathread

[crazy canuck]

It changes Joan if you take a very long term view.

Oil is a finite resource.  If Norway never pumps the oil lying in its territory that is that much less oil that will ever be burned.

We run out of time long before we burn the last ounce of oil.

[The Minsky Moment]

Oil is not a finite resource in an economic sense.  It will become (and already is becoming) obsolete long before physical quantities, which remain quite abundant, will be depleted.  When the day comes that we stop burning oil and gas, there will still be plenty left over - and it matters little whether it is in Norway, the Burgess Shale or the Arabian desert, or elsewhere.

How much oil and gas are burned before that happens will be a function of how quickly governments use mandates and taxes to suppress demand, and how quickly effective alternatives are taken up and deployed.

[Tamas]

There's an Economist article around the London floods, and in it I found this:

A particular issue is the Thames barrier, which stops tidal floods from washing back up into the city. It was closed just ten times in the decade after construction finished in 1981. But since 2010 it has closed 80 times. The study predicted that "once-a-century sea level events are expected to become annual".

Maybe I am misunderstanding it, but that sounds extraordinary. To me this means the risk of tidal floods washing into London have increased nearly tenfold since the 1980s. Things are not looking good are they. 


https://www.economist.com/britain/2021/07/31/londons-flooding-is-sure-to-worsen

[mongers]

There's an Economist article around the London floods, and in it I found this:

A particular issue is the Thames barrier, which stops tidal floods from washing back up into the city. It was closed just ten times in the decade after construction finished in 1981. But since 2010 it has closed 80 times. The study predicted that "once-a-century sea level events are expected to become annual".

Maybe I am misunderstanding it, but that sounds extraordinary. To me this means the risk of tidal floods washing into London have increased nearly tenfold since the 1980s. Things are not looking good are they. 


https://www.economist.com/britain/2021/07/31/londons-flooding-is-sure-to-worsen

Yep, but I suspect the large majority of people will only realise things are serious when the water is lapping around their ankles or coming through the sills of their cars.

[The Larch]

There's an Economist article around the London floods, and in it I found this:

A particular issue is the Thames barrier, which stops tidal floods from washing back up into the city. It was closed just ten times in the decade after construction finished in 1981. But since 2010 it has closed 80 times. The study predicted that "once-a-century sea level events are expected to become annual".

Maybe I am misunderstanding it, but that sounds extraordinary. To me this means the risk of tidal floods washing into London have increased nearly tenfold since the 1980s. Things are not looking good are they. 


https://www.economist.com/britain/2021/07/31/londons-flooding-is-sure-to-worsen

Hundredfold, if my mind is not too foggy right now. The risk went from once in a century to once per year.

[Sheilbh]

There's an Economist article around the London floods, and in it I found this:

A particular issue is the Thames barrier, which stops tidal floods from washing back up into the city. It was closed just ten times in the decade after construction finished in 1981. But since 2010 it has closed 80 times. The study predicted that "once-a-century sea level events are expected to become annual".

Maybe I am misunderstanding it, but that sounds extraordinary. To me this means the risk of tidal floods washing into London have increased nearly tenfold since the 1980s. Things are not looking good are they. 


https://www.economist.com/britain/2021/07/31/londons-flooding-is-sure-to-worsen

It's a litttle misleading. The barrier does two things - it stops tidal surges during high tide, but it also is used to control the risk of river floods so large amounts of water running into the Thames, it does this by basically creating a reservoir - so at low tide it stops the sea and creates space for water running into the Thames to fill which can then be slowly released. About two thirds of when the barrier is raised is because of the fluvial risk rather than a tidal surge.

The real shift isn't the tidal surges (though that is changing but the increased river flooding/flash storms). So in the first decade it was raised 6 times for tidal surge and 4 times for fluvial surge; in in the 90s it was raised about 40 times for tidal surges and 17 times for fluvial surge; then in the 00s it was raised about 30 times for tidal surge and 19 times for fluvial surge; in the 10s it was raised 30 times for tidal surges but 50 times for fluvial surge.

What's also worth noting is that it basically has big outlier now. So it used to be fairly regular and was used 2-3 times a year. Now that's still the case but you have more extreme years - so generally it goes up about 5 times a year in the 2010s (and that's been the average since the turn of the century), but it was used 50 times in 2013-14 (9 for tidal surge, 41 for fluvial) which I think reflects swings from big drought/heatwave years to more stormy floody years.

What has changed is more and more fluvial risk of Thames flooding and especially flash flooding (like 2013-14), not tidal surge (which has not really fluctuated that much since the 90s) and more and more outlier years. So I think it's a little different than just the risk of tidal flooding has increased that much and in fact the sea levels haven't risen as much as the designer built in to the Thames Barrier - but as I say the real issue that it's dealing with is far more flooding of the Thames.

Also key is that it was only designed to be at its best until 2030 - from 2030 onwards it will start to decline in effectiveness and there is more risk of an extreme weather event basically breaching the barrier. But the current Environment Agency plans are not to replace it until 2070 because it was designed with the expectation of sea levels rising (up to 2030 which is its useful life) and it hasn't yet hit those levelse. So instead there's plans to basically maintain it until 2050 and then slightly build it up before replacing it in 2070 - which strikes me as risky but it is the cheaper option (at only £3-4 billion) - possibly also using some of the estuary marsh lands as tidal reservoirs. There have been proposals to move the barrier further down the estuary and make it bigger and able to deal with the worst possible predictions from the Met Office for tidal surges in the next century. But Environment Agency (at least as of, I think, 2015 when they announced their plans) has decided that's too expensive - at about £7-10 billion.

Edit: And that swing in weather is really demonstrated in the "from 2010" stat because for 2011 and 2012 the barrier wasn't raised at all and in 2014 and 2015 it was only raised once. I could be wrong but I imagine those were heatwave/drought years. That used to be an outlier but now it sits alongide 2013-14 when it was raised 50 times. So we're seeing more extreme years causing either below average use or wildly above average use.

[mongers]

Southern Turkey continues to burn, fires are also widespread Greece, Northern Lebanon, parts of Syria and and now in Sardinia/Italy.

[Syt]

Read that Greece had temperatures in the mid-40s, with nighttime lows around 30 in urban areas

[Sheilbh]

Southern Turkey continues to burn, fires are also widespread Greece, Northern Lebanon, parts of Syria and and now in Sardinia/Italy.

From the European Forest Fire Information Service:

Apparently Greece is experiencing a lot of forest fires but the emergency servies have, so far, been very successful in their response. And the worst months are normally September/October.

[mongers]

Southern Turkey continues to burn, fires are also widespread Greece, Northern Lebanon, parts of Syria and and now in Sardinia/Italy.

....
Apparently Greece is experiencing a lot of forest fires but the emergency servies have, so far, been very successful in their response. And the worst months are normally September/October.

Shelf, ever the optimist I see. 

Desperate scenes in Southern Turkey, some villages have been devastated, several losing more than half of their houses, along with the deaths of locals.

Saw and Al Jazeera item from the village of Matavgav (?), 60 of the 100 plus houses gone and some locals couldn't contact their german and turkish neighbours, eventually they found them burnt to death by the side of their destroyed house. 

Several people have said these fires are so ferocious, unlike those of the pasts; what do you do in that situation, stay to try to protect the family home or run for your life, taking nothing with you?

[Sheilbh]

Shelf, ever the optimist I see. 

I think it's pretty pessimistic - September/October is likely to be worse

[Syt]

https://www.theguardian.com/environment/2021/aug/05/climate-crisis-scientists-spot-warning-signs-of-gulf-stream-collapse

Climate crisis: Scientists spot warning signs of Gulf Stream collapse

A shutdown would have devastating global impacts and must not be allowed to happen, researchers say

Climate scientists have detected warning signs of the collapse of the Gulf Stream, one of the planet's main potential tipping points.

The research found "an almost complete loss of stability over the last century" of the currents that researchers call the Atlantic meridional overturning circulation (AMOC). The currents are already at their slowest point in at least 1,600 years, but the new analysis shows they may be nearing a shutdown.

Such an event would have catastrophic consequences around the world, severely disrupting the rains that billions of people depend on for food in India, South America and West Africa; increasing storms and lowering temperatures in Europe; and pushing up the sea level off eastern North America. It would also further endanger the Amazon rainforest and Antarctic ice sheets.

The complexity of the AMOC system and uncertainty over levels of future global heating make it impossible to forecast the date of any collapse for now. It could be within a decade or two, or several centuries away. But the colossal impact it would have means it must never be allowed to happen, the scientists said.

"The signs of destabilisation being visible already is something that I wouldn't have expected and that I find scary," said Niklas Boers, from the Potsdam Institute for Climate Impact Research in Germany, who did the research. "It's something you just can't [allow to] happen."

It is not known what level of CO2 would trigger an AMOC collapse, he said. "So the only thing to do is keep emissions as low as possible. The likelihood of this extremely high-impact event happening increases with every gram of CO2 that we put into the atmosphere".

Scientists are increasingly concerned about tipping points – large, fast and irreversible changes to the climate. Boers and his colleagues reported in May that a significant part of the Greenland ice sheet is on the brink, threatening a big rise in global sea level. Others have shown recently that the Amazon rainforest is now emitting more CO2 than it absorbs, and that the 2020 Siberian heatwave led to worrying releases of methane.

The world may already have crossed a series of tipping points, according to a 2019 analysis, resulting in "an existential threat to civilisation". A major report from the Intergovernmental Panel on Climate Change, due on Monday, is expected to set out the worsening state of the climate crisis.

Boer's research, published in the journal Nature Climate Change, is titled "Observation-based early-warning signals for a collapse of the AMOC". Ice-core and other data from the last 100,000 years show the AMOC has two states: a fast, strong one, as seen over recent millennia, and a slow, weak one. The data shows rising temperatures can make the AMOC switch abruptly between states over one to five decades.

The AMOC is driven by dense, salty seawater sinking into the Arctic ocean, but the melting of freshwater from Greenland's ice sheet is slowing the process down earlier than climate models suggested.

Boers used the analogy of a chair to explain how changes in ocean temperature and salinity can reveal the AMOC's instability. Pushing a chair alters its position, but does not affect its stability if all four legs remain on the floor. Tilting the chair changes both its position and stability.

Eight independently measured datasets of temperature and salinity going back as far as 150 years enabled Boers to show that global heating is indeed increasing the instability of the currents, not just changing their flow pattern.

The analysis concluded: "This decline [of the AMOC in recent decades] may be associated with an almost complete loss of stability over the course of the last century, and the AMOC could be close to a critical transition to its weak circulation mode."

Levke Caesar, at Maynooth University in Ireland, who was not involved in the research, said: "The study method cannot give us an exact timing of a possible collapse, but the analysis presents evidence that the AMOC has already lost stability, which I take as a warning that we might be closer to an AMOC tipping than we think."

David Thornalley, at University College London in the UK, whose work showed the AMOC is at its weakest point in 1,600 years, said: "These signs of decreasing stability are concerning. But we still don't know if a collapse will occur, or how close we might be to it."

Original article: https://www.nature.com/articles/s41558-021-01097-4.epdf

[The Larch]

If that happens we're truly fucked.

[The Brain]

Others have shown recently that the Amazon rainforest is now emitting more CO2 than it absorbs

And people still want to save it.

[Syt]

https://www.reuters.com/business/environment/un-climate-report-likely-deliver-stark-warnings-global-warming-2021-08-05/

U.N. climate report likely to deliver stark warnings on global warming

LONDON, Aug 5(Reuters) - Eight years after its last update on climate science, the United Nations is set to publish a report Monday that will likely deliver even starker warnings about how quickly the planet is warming – and how damaging the impacts might get.

Since the last report by the U.N. Intergovernmental Panel on Climate Change (IPCC) in 2013, both greenhouse gas emissions and the average global temperature have only continued to climb.

The new report will forecast how much more emissions can be pumped into the atmosphere before the average global temperature rises more than 1.5 degrees Celsius. That revised carbon budget may serve as a guide to governments as they map out their own emissions-cutting plans before a major U.N. climate conference in November.

Scientists say the world must halve global emissions by 2030 and cut them to net-zero by 2050 in order to prevent global warming above 1.5C, which could trigger catastrophic impacts across the globe.

But climate change already is fuelling deadly and disastrous weather across the globe. Nearly all of the world's glaciers are melting faster. Hurricanes are stronger. Just this year, unprecedented rains unleashed floods across parts of central China and Europe, while wildfires are tearing across Siberia, the U.S. West and the Mediterranean.

"The report will cover not only the fact that we are smashing record after record in terms of climate change impacts, but show that the world today is in unchartered territory in terms of sea level rise and ice cover," said Kelly Levin, chief of science, data and systems change at the Bezos Earth Fund philanthropy.

Overall, the report "will underscore the urgency for governments to ramp up climate action," she said.

And while the 2013 report said it was "extremely likely" that human industry was causing climate change – which suggests scientists were at least 95% confident in that statement – this year's report will likely use even stronger language.

"Obviously, it is going to be stronger than what we had in the past because of the growing warming of the planet," said Corinne Le Quéré, a climate scientist at the University of East Anglia who has contributed to previous IPCC assessments.

"That's going to be one of the main points. It will be discussed very, very carefully, and scrutinised," Le Quéré told reporters.

WHAT IS THE IPCC?

Since its establishment in 1988, the IPCC has released five so-called Assessment Reports updating the established science on climate change, its impacts, future risks and ways to tackle the problems.

But the IPCC itself is not made up of scientists. The panel includes government representatives from 195 countries who commission assessments from experts and academics across the world.

In drafting those assessments, scientists consider thousands of individual studies published since the last IPCC report. To finalize their latest assessments for the upcoming report, scientists have been meeting virtually with policymakers since July 26, scrutinizing the details and language used in the draft.

Governments can suggest changes to the text, but those must be agreed by consensus. The scientists then must ensure the changes are consistent with the scientific evidence.

Monday's report is actually just part of what will go into the final Sixth Assessment Report, or AR6, when it is released in 2022.

The AR6 synthesis report will also include two other major chapters coming out next year – one on climate change impacts on communities, societies and economies and how they might adapt to cope, and another on ways of curbing emissions and reining in climate change. And it will include findings from three special reports published since 2013, on the 1.5C threshold, on the world's oceans and frozen regions, and on land use and degradation.

But Monday's chapter is one of the most highly anticipated, particularly after being delayed for months because of the COVID pandemic. Unlike the previous assessments, the chapter will use five possible emissions trajectories the world could follow rather than the previous four scenarios.

"Emissions scenarios are not intended to say: 'This is the future: pick one'," said Ko Barrett, vice chair of the IPCC. "Policies are being implemented all the time, and the science is changing all the time, so it is just not fair to say we are on a certain trajectory."