Changing Attitudes: Climate Change

[raz.org.rain]

 Methuselah we're likely as a sort of crossroads where multiple effects of climate change are interacting in a way that was unexpected. The issue I've found with much of the climatological debate is that they all assume climate equilibrium and that their theory works in isolation, so we don't have much of an understanding as to how multiple changes will interact in tandem.

If I had to guess, I would say that expanding Hadley cells and a northward migration of the jet stream are probably occurring much faster than expected. But as we're all too aware, the climate is a very erratic system that can be difficult to predict at the best of times.
 

 

[WYorksWeather]

2 hours ago, blizzard81 said:

1920's and 30's also abysmal for cold winters in the UK. 

 

I don't think anyone disputes that there have been shorter periods in the past which have seen a relative lack of snow and/or ice. But the longer term trend is pretty clear - when you take 30-year averages, we see very strong trends towards warmth in a way that just didn't happen in the past.

Here's an example comparing the 1976 heatwave to the 2018 heatwave. The UK is quite isolated in 1976, with only a few other major warm anomalies. But in 2018, warm anomalies are almost everywhere, not just a few scattered locations.

[blizzard81]

 WYorksWeather The arctic looks quite a bit colder in 2018 compared to 76.

[WYorksWeather]

 blizzard81 Definitely don't disagree with you. I'm not saying 2018 was warmer absolutely everywhere. But it is in the vast majority of cases. If you also look at the extent of the red colours, you can see that June 2018 has a much greater geographic extent of the more extreme events as well.

It's just a matter of maths in the end. In the 1980s, the climate scientist James Hansen used to go around to news studios with a set of dice with four faces above average, one average, and one below average, just to illustrate roughly the probability and how things had changed since the 1950s. In a recent update, he has now stated that compared to mid-20th century, you could now have five out of six faces above average, and one to cover both average and below average.

We can pretty clearly see this in records like the CET - there is a very notable lack now of months below the 1961-1990 average. Of course we still get below average or near average months from time to time, but they're really not that common any more.

[cheeky_monkey]

 WYorksWeather except in the prairie provinces particularly Alberta where i live where there have been a succession of colder than average years ..2023 should buck that trend though 

[WYorksWeather]

 cheeky_monkey Yeah sure - same as I said to Blizzard above. There will always be exceptions to the rule. But they don't disprove the fundamental point which is that heatwaves are far more common now than at any point in the instrumental record, and based on reconstructions probably much further back than that. People used to talk about the Medieval Warm Period as a comparator, but now you have to go back at least to the Holocene Climatic Optimum several thousand years ago, or possibly even to the Eemian period about 130,000 years ago.

[raz.org.rain]

 WYorksWeather weirdly enough I was reading about that earlier 

ancient carbon emissions similar today global warming | University of Southampton

WWW.SOUTHAMPTON.AC.UK

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56 Million Years Ago A Period Of Abrupt Global Warming Known As The Paleocene-Eocene Thermal Maximum (PETM), Was Caused By A Massive Release Of Greenhouse...

 

[WYorksWeather]

 raz.org.rain The PETM was exceptionally extreme though. It's very highly doubtful we would reach those temperatures this century even if you assume climate policies are actually reversed. I don't think crocodiles at the poles by 2100 is a reasonable scenario.

[raz.org.rain]

 WYorksWeather crocodiles at the poles would be a very, very extreme scenario. I do believe we're heading for a thermal maximum state though, probably within a few centuries. Given that such transitions usually take thousands of years, I'd imagine that nature wouldn't have time to adapt. That's where the danger lies, when you've got subtropical synoptics pushed beyond the Arctic circle and the local biome can't survive it. 
 

Nisbet, Manning et al. hypothesised that an ice age termination event could already be underway, based on methane concentrations. Others such as Schellnhuber, Steffen, Rockström et al. go even further with their suggestions and contemplate the likelihood of a hothouse state.

Fascinating and frightening at the same time. Everything would suggest that we're rapidly exiting the interglacial cycle altogether, we just don't know what comes afterwards and if we can adapt to it.

[cheeky_monkey]

 WYorksWeather never said they do ..its just an oddity that i live in the only area on the planet that has had a succession of colder years 

[WYorksWeather]

 cheeky_monkey Yeah it's interesting to think why that is. I don't think there's any real obvious reason why we should expect parts of Canada to be colder than average. Does La Nina correlate to cooler temperatures in Alberta, as a rule? If not, then probably just internal variability.

[SollyOlly]

 cheeky_monkey I'm envious!  

[WYorksWeather]

 raz.org.rain I think the reason such scenarios don't get a lot of attention is just due to the natural way we tend to think about these things, which is usually to plan no more than 100 years ahead. Barring life extension technology in my lifetime, even someone like me who is relatively young should expect to be dead in 100 years, and therefore most of us naturally consider the far future a very low priority. This is of course human nature, and is why we're in this mess in the first place.

In terms of ice ages, I've just been reading about it and it's actually quite interesting. Our current epoch is the Quaternary glaciation, which is still ongoing since there is still ice at the poles. However, it can also be considered a part of a much larger Late Cenozoic Ice Age, during which polar ice caps appeared and disappeared at least four times. The alternative is of course the greenhouse / hothouse state, where there are no ice caps for a prolonged geological period.

The question is whether we can heat the Earth sufficiently to melt the polar ice caps entirely, or whether we can get close enough that such a level of warming becomes unavoidable. Apparently the ice caps began to form (at the Antarctic) when the temperature dropped to around 5C above the 1961-1990 average, around 34 million years ago.

The point of tipping to hothouse state can't be below about 3C above 1961-1990 because the Eemian interglacial period (110,000 years ago or thereabouts) was around that warm, and of course we then descended into another glacial period.

I don't think we'll reach the ice age termination tipping point in this century, unless either our climate models are too optimistic, or emissions trajectories are worse than current policies scenarios, or probably an element of both. We'd need about 3C of additional warming by the end of the century to make it a reasonable possibility. This is a separate discussion to 'ordinary' tipping points - 3C of warming would wreck coral reefs, the Amazon, probably shut down AMOC, and melt the entire Greenland ice sheet, but it wouldn't necessarily tip us to a hothouse state.

Beyond that though, of course if you extend into the 22nd century, unless emissions reach net zero, warming will continue, so it may be possible we cross the tipping point to a hothouse. One thing that does seem impossible though, even in theoretical exercises, is that the Earth can't end up like Venus, at least not until the warming sun eventually boils the oceans in a few hundred million years. There isn't enough fossil fuel in the entirety of the Earth's crust.

 

 

[raz.org.rain]

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Edited March 1 by raz.org.rain
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[Nath]

Whatever we do or dont do in the UK is futile. Net Zero carbon is basically a scam to tax and control us.  We are making ourselves poor, hungry and risking energy blackouts for literally nothing.

 

 

[WYorksWeather]

 Nath China has about 20x our population. Their plans are clearly insufficient, but that's not a good reason for us to do nothing.

[Nath]

 WYorksWeather We dont need to do anything. Nothing we do in the UK will make even 1/1000000 of a degree difference, yet it will cause immense harm, poverty and deaths from said poverty!

 

Net Zero is all one big con IMO.

[WYorksWeather]

 Nath The same could be applied to every problem. No donation to charity will solve any major world problem by itself, so no one should donate to charity or volunteer. Politicians are elected by the votes of millions, so voting is pointless. Both of those statements would naturally follow from what you're saying.

Before I can answer the point about a 'con', I'd like to first ask the following. Which of the following best describes your current view (in other words, which bit of the mainstream view do you consider to be a 'con')? It would also be helpful to understand why.

• The Earth isn't warming
• The Earth is warming, but it's not primarily due to humans
• The Earth is warming, it's primarily due to humans, but there's nothing we can/should do about it in the UK

[raz.org.rain]

I guess we'd better start buying our beachfront properties in Greenland before the value skyrockets then.

[LetItSnow!]

The first step we need to take is to make our urban areas greener. We know that more trees cools the surrounding area by quite a considerable margin and overall has a positive effect. We need our streets lined with trees when possible, for our parks to be a bit more wild and for urban areas to have more allocated meadows and forested areas. That could be a crucial step at reducing the intensity of heatwaves in urban areas. Then we can get onto the topic of c02 removal and/or aerosols. 

[WYorksWeather]

 LetItSnow! Definitely one of the very many things that would be needed. Under a moderate warming scenario of about 3C globally by 2100, here are the conditions we'd need to tolerate.

By the end of the century, at a minimum we need infrastructure in London and the South East to be tolerant of temperatures up to 45C in summer (scaled down further north, so maybe 42C at my location, 40C for Newcastle, 38C for Scotland). We also need coastal infrastructure to be protected against sea level rises of a metre (possibly higher if ice-sheet feedbacks are closer to worst-case), or if this can't be justified, the alternative is abandonment. We should also expect similar annual rainfall, but with seasonality, concentrating heavy rainfall events in the winter with drier summers. 

I think people vastly underestimate the costs of adapting to this. Coastal defences don't come cheap, and tolerating temperatures well into the 40s for most of England during summer heatwaves means air conditioning will become a requirement rather than a nice-to-have. None of this will come cheap.

[Methuselah]

It's not that climate scientists keep moving the goalposts; it's that deniers don't have any goalposts: 

 

 

[Methuselah]

An interesting lecture from Grisham College:

 

[Gowon]

 WYorksWeather

Yeah it's interesting to think why that is. I don't think there's any real obvious reason why we should expect parts of Canada to be colder than average. Does La Nina correlate to cooler temperatures in Alberta, as a rule? If not, then probably just internal variability.

This might be of interest:

Widespread Reforestation Has Buffered The Eastern US Against Climate Change

WWW.IFLSCIENCE.COM

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The findings show just how powerful trees can be on a regional scale.

 

[Gowon]

I consider myself as a climate agnostic...