How heatwaves will change around the world for every 1°C increase in global average temperatures
From the UNIVERSITY OF NEW SOUTH WALES
Summer in some regions of the world will become one long heatwave even if global average temperatures rise only 2°C above pre-industrial levels and certain regions may become close to unliveable if temperatures increase by 5°C.
CREDIT Anna Jiménez Calaf on Unsplash
Even with just a 1.5°C increase in global temperatures there are significant changes to the length, intensity and frequency of heat waves in every part of the world.
That’s the finding of new research by Dr Sarah Perkins-Kirkpatrick from the ARC Centre of Excellence for Climate system Science published today in Scientific Reports that divides the globe into 26 regions and looks at how heatwaves will change with every 1°C rise in global temperatures.
When all the regions are combined, for every 1°C of warming during summer the researchers found there would likely be:
- An extra 14.8-28.2 heatwave days.
- Heatwaves would be 3.4-17.5 days longer.
- The peak intensity of heatwaves will increase 1.2°C-1.9°C.
But it’s when the researchers drilled down to the region-by-region level that the most startling changes appeared.
“We were particularly surprised by the alarmingly fast increase in heatwave days in the tropics where some regions transition to an almost constant heatwave state with just a 2°C rise,” said Dr Perkins-Kirkpatrick.
“We also found that even with just a 1.5°C increase in global temperatures, almost all regions started to experience heatwave events every four years that once only occurred every 30 years. If global temperatures were to rise by 5°C such events would occur every year.”
By dividing the globe into 26 distinct regions, the research also highlighted the wide variation in heatwave responses across the world. There was a much sharper increase in peak temperatures of heatwaves over the Mediterranean and Central Asia.
Meanwhile tropical regions saw many more additional heatwave days and longer continuous heatwaves than other parts of the world.
The only decline to appear across the research was the number of discrete heatwave events in two regions, Central America and Eastern Africa. But this was not good news because these regions also saw the greatest increase in heatwave days.
Effectively what had once been two heatwaves had now merged into one long heatwave.
“This study is yet another wake-up call to policymakers that we need to act on limiting the rise in global average temperatures due to human caused climate change,” Dr Kirkpatrick said.
“Without prompt action, there could be disastrous consequences for many regions around the world.”
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Paper: Changes in regional heatwave characteristics as a function of increasing global temperature. (doi:10.1038/s41598-017-12520-2)
See this interactive map showing how heatwaves will change with global warming
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First off the tropics are the places where CO2 has the least impact.
These morons seem to be taking current temperatures and blindly adding 2C or 5C to them.
They also seem to be assuming that a heat wave is whenever temperatures get above a preset level. Period.
A heat wave is defined as a certain number of degrees above the average for that time of year. If the world did warm, the definition for a heat wave won’t change, but the average from which it is calculated will.
90C in March is a heat wave for NYC. On the other hand it’s cooler than normal for Phoenix in July.
I believe you meant 90 F, and yes I live in the Phoenix area and 90 in March is warm, 90 F down here is only warm, hot is 105+, As to these moron’s paper it was Richard Lindzen that has pointed out to these educated idiots that in the last several million years the tropics have not varied more than + or – 1C. Should that not be taught in climatology 101?
“This study is yet another wake-up call to policymakers that we need to act on limiting the rise in global average temperatures due to human caused climate change,” Err isn’t there a missing step there. Correlation is not causation
Good. No need to travel as far low-lands and south.
CIMP5 models, RCP 8.5 scenario (described as “business as usual”) for 2006-2100 and “historical experiment” for 1861-2005. Plus use of CSEM models for “internal variability” Comparison at regional level, if I understand the methods correctly, is to *modelled* pre-industrial heatwaves, not based on actual data from 1861-1890. AFAICT, no actual historical heatwave data is used in the paper; an odd omission given the ~1C rise from an arbitrary 19th century temperature level — history might not only reveal what the actual heatwave effects from the warming so far have been, but also whether the CIMP5 “historical experiment” runs demonstrate any skill at all in reproducing the historical results in this matter.
Dale
That’s weird. How can an RCP8.5 be ‘business as usual’ when RCP supposedly means heating if the climate sensitivity is much higher than is generally expected?
They are conflating an emissions rate and a climate sensitivity. It should be, I believe, ‘atmospheric heating response if the climate sensitivity is really high AND we have emissions continue to rise as they have for the past 20-30 years’. It is ’emissions as usual’ with ‘climate response not as expected by anyone in their right mind’.
Not even the British Colombia Green Party’s Mr Weaver (author of the RCP6.0 model in Victoria) believes that RCP8.5 represents anything real. And that is really saying something.
RCP 8.5 posits that there is no enforced reductions on emissions, hence “business as usual”. Of course, it also assumes a lot of other things which are *extremely* unlikely to happen, such as unbounded growth of fossil fuels despite it being a limited natural resource.
RCP 8.5 *isn’t* different in terms of climate sensitivity. That’s baked into the models, the different RCP just alter the emissions . So by providing unrealistically high emissions, combined with models that seem to have too high CO2 sensitivity and/or overrate the effect on concentrations from emissions, you are provided with a sort of worst-case-scenario to make extreme claims about. This article wants to go all the way up to +5C, and it needs RCP 8.5 to do so.
Heatwave doesn’t have a formal definition and in the case of this study would be a three-day period where the Tmax exceeds the 90th percentile for the running 14-day mean for at least three consecutive days in a five-month summer (May-Sept for NH). The percentiles are determined from 1861-1890 model output. Obviously, in regions nearer the poles exceeding the 90th percentile may not remotely represent an “unlivable” temperature. In hotter regions where the variability is small, exceeding the 90th percentile may not be much of a jump. But since the article seems confine to examine what changes the *models* project, in the absence of evidence that the models have skill in this particular area I see no reason why we should take this as likely, let alone good enough to inform policy.
“Average” hides a lot of things. For example, are high temperatures getting higher or are low temperatures getting higher or both. If the first, then we might expect more heatwaves. If the second, it could mean the incursion of urban heat island effects on nighttime temperatures. If both, then it might be either real overall warming or UHI or both.
Perhaps those questions might have been answered already: http://hallofrecord.blogspot.com/2007/08/tomorrow-not-so-variable-temperatures.html
What does unliveable mean in that report? I take it they don’t mean uninhabitable in the true sense but implying some form of choice.
Summer could be one long heatwave
That’s funny because this summer here in rural west MD is another added to the “didn’t get to 90F” list.
It’s another model based paper…
Also, check out the references.
————————————
Changes in regional heatwave characteristics as a function of increasing global temperature
The Paris Agreement calls for global warming to be limited to 1.5–2 °C. For the first time, this study investigates how different regional heatwave characteristics (intensity, frequency and duration) are projected to change relative to increasing global warming thresholds. Increases in heatwave days between 4–34 extra days per season are projected per °C of global warming.
Analysis of two climate model ensembles indicate that variation in the rate of heatwave changes is dependent on physical differences between different climate models, however internal climate variability bears considerable influence on the expected range of regional heatwave changes per warming threshold. The results of this study reiterate the potential for disastrous consequences associated with regional heatwaves if global mean warming is not limited to 2 degrees.
http://www.readcube.com/articles/10.1038/s41598-017-12520-2
Heat waves occur in temperate regions when the jet stream (which steers most storms) moves far to the north in late spring or summer. In areas south of the jet stream, very few clouds form, and the atmosphere heats up due to the high sun angle and long days (and short nights). But warm air under a heat wave tends to expand and push further north.
However, the total mass of air over the poles tends to remain nearly constant, and if warm air is pushing north at some longitude under a heat wave, the built-up air over the pole has to push south somewhere else (either east or west of the heat-wave area), bringing unseasonably cool temperatures there.
There was a long, major heat wave over Europe during the summer of 2003, and since many European homes lack air-conditioning, people who could not escape to the coast were suffering from the heat, and some were blaming “global warming” for the excessive heat. But during that same summer, the east coast of the United States was unusually cool and rainy, with temperatures rarely getting above 75 degrees, in areas where the average high temperature in July and August is usually over 80 degrees..
The air mass balance over the Arctic doesn’t change much–if warm air is pushing northward along one meridian, cold air must be pushing southward along another.
There is page on Wattsupwiththat which shows temperatures above 80 degrees north latitude. While there is much variation from year to year during the cold season (October through April), these temperatures seem to stabilize around 276 K (about 37 F) every year between June and September. Once there is open water in parts of the Arctic Ocean, evaporation from open water absorbs heat from the atmosphere and maintains air temperatures only slightly above freezing throughout the summer. This provides a consistent heat sink, which can send cool, damp air southward to break heat waves.
“But during that same summer, the east coast of the United States was unusually cool…”
Right next door in Western Asia temperatures were 20 C below normal during the Great European heat wave of 2003. The cause was a stalled ‘Omega pattern” as we call them in N America. A loop of the jet stream blocked the eastward movement of the hot air. That’s all. The stall was caused by a quiet sun, not so?
I’d hate to see their non-excellent climate system science.
Two degrees is the equivalent of moving from the Upper Levels highway in North Vancouver to the Sea Bus terminal on 11th St. It is also the difference in Toronto between the 15th of October and the 30th of October during an average year. It is greater than the difference between living in Toronto and Waterloo or Peterborough in August or October.
How on earth will we survive? How will ‘nature’ cope? What about the little field mice? (They are so cute.)
University of New South Wales is best know for having an end of the Sydney Cricket Ground named after them. This is the first time outside cricket that I have heard of them. I guess they needed to jump on the AGW gravy train.
I really want to run that test on these people, the one that asks them if they can tell the difference between 70F and 70.5F or 69.5F. See, that’s the real deal. It’s the part that tells you this hypothetical probability of theirs is simply a hand out in search of more grant money. Grant money comes from taxes. We’re all taxpayers, aren’t we? We should be demanding our money’s worth in proof of results.
Since I do not believe for one teensy weensy second that any of these air-conditioned, cosseted prognosticators inhabiting closed environments such as big buildings, I’d be happy to set their thermostat at an 0.5F difference in temperature, up and down, for a week, and then ask them if they really notice the difference. I don’t think they would be able to do so.
I had to run the furnace this morning, because the overnight temp was 49F and the windows were open a little. We had two weeks of late heat from Irma’s driving away the cooler air coming down from the north with that blocking pressure font, but it’s gone now.
When I got up, the thermostat read 72F, but I waited until it said 70F, then turned on the system. I leave it at 73F, period. The thermostat and the thermometer across from it show the same indoor temps. Frankly, I can’t tell much difference between 73F and 75F, and I don’t think these researchers can, either, never mind an 0.5F difference up or down or sideways. And since an indoors environment is a closed system, it’s more stable than an outdoors system, which is subject t chaos patterns.
This is all nonsense. In my view, their study is baloney. We don’t live on the Mad Max planet or Khan’s planet, or Arrakis, therefore, other than a begging paper published to get some cash, the paper is another exercise in “how to con the taxpayers again and get a pat on the head”.
Oh, yeah – since none of youse guys have taken my challenge (show the +/- 0.0 differences on a linear graph over real time), I will do it myself. I just have to get some graph paper from Staples and some color markers. And a ruler. School supplies will probably be on sale again. I might get a discount.
“A heat wave is a prolonged period of excessively hot weather, which may be accompanied by high humidity, especially in oceanic climate countries. While definitions vary, a heat wave is measured relative to the usual weather in the area and relative to normal temperatures for the season. Temperatures that people from a hotter climate consider normal can be termed a heat wave in a cooler area if they are outside the normal climate pattern for that area.”
This fails immediately without even looking into examples how heatwaves develop in different areas of the world.
1) Global temperatures only need to warm about another 1c to achieve only 2°C above pre-industrial levels.
2) Maximum temperature records have only been broken by no more than the rise in global temperatures.
“A definition based on Frich et al.’s Heat Wave Duration Index is that a heat wave occurs when the daily maximum temperature of more than five consecutive days exceeds the average maximum temperature by 5 °C (9 °F), the normal period being 1961–1990.”
3) An increase of 1 °C locally won’t make an heatwave for anywhere in the world, unless the changing weather patterns allow it in the first place.
4) Average maximum temperatures for general definition require to be 5 °C (9 °F) higher to be generally accepted as an heatwave.
5) Definitions vary, but length of at least 3 to 5 days usually required.
“Without prompt action, there could be disastrous consequences for many regions around the world.”
So – what exactly IS that ‘prompt action’? And how exactly is it going to give us the controls to the global thermostat?
Define ‘disastrous consequences’, while you’re at it.
Don’t forget the basis of all research is: find out what the paymaster wants you to say, then bend your research to what the paymaster wants, otherwise you don’t get paid!
I think this needs a nice song.
Oh joy. That means the rain will be warmer in the UK.
Okay…lets test their hypothesis. Where can we get an Earth that has recently warmed about 1 degree C? Oh hey…this one. Do we have any evidence that heat waves have increased as they have predicted? It appears to be just the opposite in the United States, despite all of the ‘adjustments’ to the contrary. I don’t really know about the rest of the world, but my guess is that the evidence falsifies their hypothesis.
But if it doesn’t, the fact that the climate models have no skill at the regional level, and that the primary theory of AGW predicts very little warming in the tropics compared to the higher latitudes, it is safe to say that this ‘study’ is no more than grant bait and alarmist foder.
So when Germans no longer fly to Miami, we are doomed?
Global warming will save lives because 20X more people die of below optimum temperature than above optimum temperature. https://wattsupwiththat.com/2015/05/21/an-inconvenient-truth-from-medical-research-cold-is-far-worse-than-global-warming-at-killing-people/
As for heat waves, just think of the increase in lemonade sales!
It’s about as likely as this claim that raining fish may be caused by Climate Change ™
http://www.npr.org/sections/thetwo-way/2017/09/28/554242564/it-rained-fish-in-mexico-authorities-say-no-its-not-the-end-times-we-think
I think that I can settle for “ARC Centre of Excrement for Climate system Science” as being a better description. This is their latest offering for continued funding from the CAGW gravy-train.
How about “Fringe of Fraud”?
I was in Florida the first 2 weeks of September. The heat there is WAY above anything we have ever had here in Alberta. So, the extra so called heat wave days we are due are not heat waves at all, just unusually warm days.
An interesting development. In order to instill fear and a sense of ‘unprecedented warming’, the government here now issues “Heat Warnings” for any day that is warm. It is just silly. We all know that when the forecasted high is over 30°C, it’s going to be hot. We don’t need some goofy “Heat Warning”.
“We were particularly surprised by the alarmingly fast increase in heatwave days in the tropics where some regions transition to an almost constant heatwave state with just a 2°C rise,” said Dr Perkins-Kirkpatrick.
I’d like to hear Willis Eschenbach’s take on this. He did a piece on clouds some time ago that showed how temperatures are naturally regulated in the tropics. When temperatures rise earlier than usual, clouds also appear sooner than usual and cool things down a bit. I really doubt the models used in this paper account properly for clouds.