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Pat's Guide to Glasgow West End

Global warming in 2020 and a sleeping giant


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It's early days, but 2020 is shaping up to be the warmest year, globally, since records began in the 19th century, and very probably the warmest year Earth has experienced since the end of the last Ice Age, 11,500 years ago. Usually, when a new record is set, it coincides with an above average intensity El Nino, which is a periodic warming of the tropical Pacific. This was the case during the record intensity 2016 El Nino (on a par with the then record 1997-98 event). 2016 is the current global temperature record year. El Ninos usually last for several months, straddling the end of one year, and the start of the following year. The global temperature anomalies for the first four months of the following year are almost always the most extreme, and this was the case in 2016.

According to the NASA GISS data, 2016 was 1.02 C warmer than the average for 1951-80. The Jan-Apr anomaly averaged 1.26 C, but only some of this large anomaly would have been due to El Nino. Something else is going on, which I'll get to later. For comparison, the weak or non El Nino (ENSO neutral) years of 2017, 2018 and 2019 had global temperature anomalies of 0.92 C, 0.85 C and 0.98 C, respectively. The Jan-Apr average for those three years was 0.98C. The May-Dec average for 2017-19 was 0.89 C, or 0.09 C less than the Jan-Apr average.

Despite no El Nino, the average anomaly for the first four months of 2020 was a whopping 1.19 C. If we assume that May-Dec monthly anomalies average the same 0.09 C less, this would give an annual global temperature anomaly of 1.13 C, obliterating the 2016 record in an ENSO  neutral year. This is quite dramatic stuff, and the questions that arise are 1) is this the start of a global warming surge, probably due to positive feedback effects starting to kick in, and 2) if so, what's causing it?

Most of the warming caused by greenhouse gases (GHGs) is not due to the direct reradiation of outgoing infrared radiation back to the surface. It's caused by positive feedback effects. For example, water vapour is a much more potent greenhouse gas than carbon dioxide, and the relatively modest amount of direct warming caused by CO2, methane, and other greenhouse gases, causes more water to evaporate from the ocean, amplifying the initial warming. Cloud formation prevents this feedback effect from becoming  'runaway'  global warming, which is what's believed to have happened on Venus.

Other positive feedback effects include the reduction of snow and ice cover, decreasing Earth's albedo, so that more sunlight is absorbed, and the release of CO2 and methane from melting permafrost, and from warmer soils due to increased bacterial activity. The release of methane from methane ice below the sea bed as the sea temperature rises, particularly under the Arctic Ocean, has also received much attention, but this is more conjectural, although there's no doubt that vast amounts of methane in ice exist there.

The ocean is the 'sleeping giant' of climate change. It's an enormous heat sink, and it's estimated that 94% of the extra energy trapped by GHGs is absorbed by the ocean, and most of that is transported to the depths. There is enormous potential for various positive feedback effects to kick in as a result of warming in the ocean, which are poorly handled by the computer models, so we don't hear much about them. It seems very likely that the recent strong anomalies in the early months of the year are due to heat being given off by the Arctic Ocean in winter. At first glance, this seems counter intuitive. Although the September minimum ice cover area in the Arctic Ocean has decreased considerably in recent years, winter cover has not changed much, but what has changed is the depth of the ice. Although satellite pictures show little change in winter area of Arctic Ocean sea ice, what they don't reveal is how much it has thinned. And, it's thinned a lot. Typically, it may only be a metre thick, when it was several metres thick in the past.

Syukuro Manabe is a retired Japanese climatologist who spent most of his career working in the US, and was an early pioneer of computer modelling of greenhouse gas effects on climate, particularly in the area of coupled ocean-atmosphere modelling. A few years ago, I watched a Youtube video of him explaining how thinning Arctic Ocean ice in winter could have a profound effect on global climate. Annoyingly, I haven't been able to find it, since. When the ice is thick, the heat from the ocean can't get through to warm the air above. But, when the ice thins appreciably, it can permeate through to warm the air above. The water below the ice is about -2 C, while the air above may be -40 C or lower in winter. So, there is enormous potential for a positive feedback effect involving warming of the air above the Arctic Ocean in winter as the sea ice thins. And what goes on in the Arctic doesn't stay in the Arctic. 

This may be responsible for the high monthly global temperature anomalies in the Jan-Apr period in recent years. If it is, then the extremely high 2020 anomalies is cause for concern, as it might be an early indication that this largely unheralded, but potentially large, positive feedback effect may be about to take off. Many ice core studies in recent years have overturned the previous misconception that climate change is always a gradual process. Analysis of Greenland ice core samples have shown that there have been very rapid sustained temperature changes in Greenland of around 10 C in the past, occurring in just a few years. 

The ocean surface water mixes with water at depth. If it didn't, there would be no oxygen, and no life, in the deeper parts of the ocean. This mixing is dependent on salinity and temperature differences. Warmer surface water expands due to the heat, so is less dense than deeper water, and therefore less able to mix. But, the evaporation at the surface makes it more saline, and this makes it more likely to sink. Recent research concludes that, as the surface of the ocean gets warmer, it will become more stratified, and less prone to sinking, so that less heat is transported downwards, thus greatly enhancing surface warming. Presumably, this will mean that the 94% figure for the amount of energy trapped by GHGs that is absorbed by the ocean will drop, and there will be a surge in atmospheric warming as a result. Yet another potentially large feedback effect that you don't hear much about.

Much of the CO2 produced by man goes into the ocean. This is dependent on the temperature of the ocean surface, and the amount of CO2 already dissolved. The colder regions absorb CO2, while the warmer regions actually outgas it. Therefore, as the oceans warm, there will be less uptake, and more outgassing. In theory, the ocean could eventually become a net emitter of CO2 to the atmosphere, a nightmare scenario. The same thing happens with oxygen. Marine phytoplankton and seaweeds produce oxygen, but it is also absorbed from the air. As with CO2, this is temperature dependent, and some warmer regions may outgas oxygen to the point where they become anoxic 'dead zones'. Such zones are often seen close to shore, as a result of fertiliser runoff, but anoxic  dead zones are increasingly being identified in warmer oceanic regions far from the influence of agriculture.

In the distant past, mass extinction events were associated with high atmospheric CO2 levels, global warming, anoxia in the oceans, and a mysterious terrestrial charcoal layer, indicating that the world burned. It only takes a small increase in atmospheric oxygen to make the world much more combustible, and high levels of atmospheric oxygen, due to outgassing from warmer oceans, and increased lightning due to a warmer climate is a plausible explanation for the charcoal layer.

https://data.giss.nasa.gov/gistemp/tabledata_v4/GLB.Ts+dSST.txt

 

 

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Today (June 1st) is the official start of the Atlantic hurricane season. The eastern Pacific's first named storm of the year, Amanda, has tracked across central America, causing a lot of flash flood damage, and is now entering the Bay of Campeche, after staying offshore and drenching the Yucatan peninsula. The US National Hurricane Center (NHC) gives it a 90% chance of restrengthening to a tropical storm in the next 48 hours, which would make it the earliest third named Atlantic storm on record. It would be rechristened 'Cristobal'. The current record for the earliest third Atlantic named storm is Colin, which was named on June 5, 2016. This very strongly suggests that global warming is extending and intensifying the hurricane season, which has always been a 'no brainer' prediction by climate scientists. The NHC predicts an above average hurricane season.

https://www.wunderground.com/cat6/deadly-flooding-in-central-america-from-amanda-new-development-in-western-gulf

Did some googling, and found that current Arctic Ocean ice volume is only the sixth lowest on record, which makes the current  extremely high Jan-Apr global temperature anomaly pretty mysterious. I still think it's related to decreasing winter Arctic ocean ice volume, but global warming is going to spring many surprises. Awaiting the May global temperature anomaly with interest. Should be out in two weeks.

 

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That is an awful lot to take in, Yonza. It seems trite to ask with the scale of what you have described - whether the much reduced traffic and, in particular, air traffic makes any difference regarding climate change?

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12 hours ago, Pat said:

That is an awful lot to take in, Yonza. It seems trite to ask with the scale of what you have described - whether the much reduced traffic and, in particular, air traffic makes any difference regarding climate change?

Good question. Regarding the reduction in CO2 output, a negligible effect. However, the decrease in particulate and sulfur dioxide (SO2) pollution as a result of reduced industrial activity and transport might actually have a short term warming effect. Global warming due to man's input of CO2 had been predicted by scientists since the 19th century, but was slower than had been expected. There was a surge of warming in the 40s, mainly in high northern latitudes, then it subsided, and the current strong warming didn't get going until the late 70s.

Some scientists have speculated that the introduction of clean air laws in the US and Europe in the 70s may have had something to do with it. Particulates (tiny soot particles) intercept sunlight, preventing it warming the surface. But, it's very complicated science, and I've seen it suggested that particulates might actually have a warming effect, by absorbing energy, and acting as microscopic 'storage heaters'. I favour the simpler explanation, that they have a cooling effect, by preventing sunlight reaching the ground.

SO2 is more straightforward. It reflects back sunlight, and has a cooling effect. The eruption of Mount Pinatubo ejected a massive amount of SO2 into the stratosphere, which had a global cooling effect of 0.2 C for two years. It was SO2 from coal fired power plants that was mainly responsible for the ecological damage caused by acid rain, as it  converts to sulfuric acid in cloud water droplets. Clean air laws have made a big difference to SO2 emissions, at least in the west, but many developing countries are still using high sulfur coal for electricity generation. It seems likely that at least some of the global warming since the 70s is due to clean air laws in the west.

Air travel is a bit complicated. Planes produce CO2, but they also create contrails, and this is another area of unsettled science. After 9/11, aircraft were grounded throughout the US, and some scientists claim that this resulted in a warming of around 1 C in the US, due to the reduction in contrails. There's another body of opinion that claims that contrails have both a cooling and a warming effect, depending on their age. Newly emitted contrails cool, while dispersed contrails act like greenhouse gases. That makes sense. Water vapour is a powerful greenhouse gas, but when it condenses to form clouds, it screens sunlight, cooling the surface, although some clouds, like the high, wispy cirrus variety, are believed to have a warming effect.

It's complicated stuff, but the short term effects of reduced transport and industrial activity, due to the coronavirus,  will have very little effect on the global warming juggernaut.

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The NASA global temperature anomaly (ref 1951-80) for May is in, and it sets a new record for the month, at +1.02 C, beating the 2016 record of +0.96 C. The annual anomaly for 2020 looks very likely to beat the mega El Nino boosted 2016 record, despite being a non El Nino year.

From Wunderground:

'Global temperature records are more likely to be set during the peak of the solar cycle--and during strong El Niño events, due to the extra heat the tropical Pacific Ocean gives up to the atmosphere. The remarkable warmth of 2020 has come in the absence of an El Niño event and during the minimum of one of the weakest 11-year solar cycles in the past century, underscoring the dominant role human-caused global warming has in heating our planet.'

That's disconcerting.

https://www.wunderground.com/cat6/may-2020-earths-warmest-may-on-record

 

 

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The latest supercomputer models are telling us that it's worse than we thought. From the Guardian:

Worst-case global heating scenarios may need to be revised upwards in light of a better understanding of the role of clouds, scientists have said.

Recent modelling data suggests the climate is considerably more sensitive to carbon emissions than previously believed, and experts said the projections had the potential to be “incredibly alarming”, though they stressed further research would be needed to validate the new numbers.

Modelling results from more than 20 institutions are being compiled for the sixth assessment by the United Nations Intergovernmental Panel on Climate Change, which is due to be released next year.

Compared with the last assessment in 2014, 25% of them show a sharp upward shift from 3C to 5C in climate sensitivity – the amount of warming projected from a doubling of atmospheric carbon dioxide from the preindustrial level of 280 parts per million. This has shocked many veteran observers, because assumptions about climate sensitivity have been relatively unchanged since the 1980s.

“That is a very deep concern,” Johan Rockström, the director of the Potsdam Institute for Climate Impact Research, said. “Climate sensitivity is the holy grail of climate science. It is the prime indicator of climate risk. For 40 years, it has been around 3C. Now, we are suddenly starting to see big climate models on the best supercomputers showing things could be worse than we thought.”

https://www.theguardian.com/environment/2020/jun/13/climate-worst-case-scenarios-clouds-scientists-global-heating

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The most northerly temperature of 100 F was recorded yesterday, at Verkhoyansk, in Siberia, which sits 70 miles north of the Arctic circle.

https://www.cbsnews.com/news/arctic-records-its-hottest-temperature-ever-2020-06-20/

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  • 3 weeks later...

Tropical storm Fay has set a new record for the earliest sixth named storm of the Atlantic hurricane season. The previous record was Franklin, on 21 July 2005. That was the year of the most active and infamous hurricane season on record, with 28 named storms, 15 of them hurricanes, including the most destructive, Katrina, and the strongest (Wilma, 185 mph).

Fay is currently packing winds of 60 mph, and will track over New York later tonight. Not expected to be particularly destructive, but there will be power outages, and some areas could get up to 6 inches of rain. More, and stronger hurricanes have long been predicted in a warmer world. September is the most active month.

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The NASA global temperature anomaly for June is just in, and it's the joint warmest June in a record going back to 1880, tying with June 2019, at 0.93 C above the 1951-80 average.

https://data.giss.nasa.gov/gistemp/tabledata_v4/GLB.Ts+dSST.txt

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Hurricane Hanna is currently making landfall in south Texas, with sustained 90 mph winds. It's the earliest 'H' storm on record. Tiny tropical storm Gonzalo reached 65 mph, but now appears to be dissipating as it enters the eastern Caribbean. There's a huge swirl off Africa which the National Hurricane Center expects to develop into a named storm. It's expected to reach the US in about 10 days as a dangerous hurricane, but could curve back out to sea. All the indications are that it's going to be a very 'busy' season.

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  • 4 weeks later...

NASA global temperature anomaly for July just in, and it's the second warmest July on record, at 0.89 C above the 1951-80 average. July 2019 is the warmest on record, at 0.95 C, and 2016 the third warmest, at 0.85 C.

https://data.giss.nasa.gov/gistemp/tabledata_v4/GLB.Ts+dSST.txt

We're now approaching the most active part of the Atlantic hurricane season. September 10 is the peak. There are currently two low pressure systems in the Atlantic, which the National Hurricane Center expect will develop into named storms. Conditions are more conducive than normal for hurricane development, and the high pressure system over Bermuda is currently strong, which would keep anything that does develop on a westerly track, making landfall more likely.

In addition, a weather system called the Madden-Julian Oscillation (MJO), which circles the globe eastwards in the tropical oceans every 30-60 days, will shortly be entering the Atlantic region. The MJO creates conditions that are very supportive for hurricanes, so we could be about to see a lot of major hurricanes barrelling westwards into the Caribbean islands, Central America and the US.

 

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  • 4 weeks later...

La Nina has  officially been declared. This is the cool counterpart of El Nino, which is a warming of the eastern tropical Pacific. La Ninas usually have a small global cooling effect, and the magnitude of this is dependent on whether the La Nina is classed as weak, moderate or strong. La Ninas usually last for a minimum of 5 months. The regional climatic effects around the globe include  reduced rainfall in east Africa. During the strong 2010-11 event, between 50,000 and 100,000 people in Somalia and neighbouring countries died of famine. It would have been far worse in the past, without international aid.

'In August, La Niña conditions were present, with below-average sea surface temperatures (SSTs) extending across the central and eastern equatorial Pacific Ocean (Fig. 1). In the last week, all Niño indices were negative, with the Niño-3.4 index at -0.9ºC and the Niño-1+2 and Niño-3 indices cooler than -1.0ºC (Fig. 2). Equatorial subsurface temperature anomalies averaged across 180°-100°W were negative (Fig. 3), with the largest departures observed in the east-central Pacific from the surface to 200m depth (Fig. 4). Atmospheric circulation anomalies over the tropical Pacific were also generally consistent with La Niña, despite sub-seasonal variability during the month. The low-level and upper-level winds were near average for the month as a whole, but enhanced low-level easterly winds were prominent across the equatorial Pacific Ocean during early and late August. Tropical convection remained suppressed over the western and central Pacific, and was near average over Indonesia (Fig. 5). Both the Southern Oscillation and Equatorial Southern Oscillation indices were positive. Overall, the coupled ocean-atmosphere system was consistent with La Niña conditions.'

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Tropical storm Sally has just formed over Florida, and is currently just about to enter the Gulf of Mexico. It has sustained winds of 40 mph, and is predicted by the National Hurricane Center to make landfall near New Orleans on Tuesday as a low end 80 mph category 1 hurricane. That would cause power outages and some structural damage, but nothing to write home about.

However, the NHC admits that there is 'some uncertainty' about the intensity, and many observers on the tropical weather forum I visit are suggesting that it could rapidly intensify up to a major hurricane category 3. There doesn't seem to be any of the usual environmental factors that would hinder development, such as dry air, wind shear, low sea surface temperatures etc.

The NHC have a social responsibility not to cause unnecessary panic, but if Sally does rapidly intensify to a major, there won't be much time for warnings to evacuate. Tropical storms have intensified to catastrophic category 4/5 hurricanes in less than 3 days in the past. Hopefully, Sally will do as the NHC predicts.

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We've been warned for many years that global warming would result in more, and stronger tropical cyclones. Yesterday, there were five named storms in the Atlantic, equalling the record for simultaneous named storms. One of them has since dissipated, but there's another system emerging from Africa to replace it. Sally will be making landfall near Mobile, Alabama tonight, as a category 1 hurricane. Tropical storm Vicky is the latest addition to the family - only the second time that 'V' has been used. Since we're only 5 days past the peak of the Atlantic hurricane season, it's almost certain that the National Hurricane Center will soon be using Greek alphabet names for the storms, only the second time they've had to do this.

At the start of the season, the Azores/Bermuda high pressure ridge was strong, and pushing storms west, threatening land. Now, it has weakened, and storms forming in the eastern Atlantic appear to be meandering harmlessly out to sea. A few may turn up on UK shores as 'remnants'. The ridge could become strong again, and October has produced some monsters in the past. What we're witnessing now is exactly what scientists predicted decades ago, and it's only going to get worse.

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Hurricane Sally has just made landfall (10 am) on the Alabama - Florida border, as a category 2 storm, with 105 mph sustained winds. It's moving inland at a very slow 3 mph, which means it'll hang around longer than most landfalling hurricanes, and cause more damage than would normally be expected for a 105 mph storm. The National Hurricane Center has warned of 'historic and catastrophic' flooding, due to the huge amount of rainfall. Pensacola, Florida, is getting the worst of it.

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  • 2 weeks later...
On 9/25/2020 at 3:37 PM, Pat said:

These poor souls living in these area. Seems they are under relentless threat of hurricanes. 'Sally' seems such a friendly name.

'Harvey' sounds friendly, too. Dumped a US record five feet of rain on Houston in 2018, and killed 68 people, with an additional 39 indirect deaths. 

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Arctic Ocean September minimum sea ice extent has declined to the second lowest in the satellite era. The record low is held by 2012. That year was anomalous, due to an unseasonal late summer storm, which broke up the ice, making it melt more quickly.

https://www.theguardian.com/world/2020/sep/21/arctic-ice-polar-ocean-shrinks-climate-change

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There are currently two named storms in the Caribbean. Gamma is a 45 mph tropical storm, which is expected to dissipate after it makes landfall in the Yucatan peninsula of Mexico in a day or so. Delta is a tropical storm south of Jamaica. The National Hurricane Center estimates Delta's winds at 60 mph, but it looks as if it might have started to rapidly intensify since the last advisory 4 hours ago. It's predicted to make landfall on Friday, somewhere between the Texas/Louisiana border and the westernmost part of the Florida panhandle, as a 100 mph category 2 hurricane, similar to Sally, which landed in Alabama at 105 mph, just three weeks ago. It'll be dreadful if it lands in the same spot.

The NHC is often very conservative with its long range intensity forecasts, and the tropical weather nerds on the Wunderground forum are thinking this could be a very dangerous major hurricane. The current apparent bout of intensification, inferred from satellite loops, supports this.

This is the 25th named storm of the season, and there's a good chance that 2020 could end up beating the 2005 record of 28 storms. Hopefully, Delta won't turn out to be the equivalent of that year's hurricane Katrina. New Orleans is currently in the centre of the cone, but that'll probably change in the days ahead.

You can follow the NHC advisories and view (almost) real time satellite loops of Delta's progress here https://www.nhc.noaa.gov/

To view the satellite pics, click 'data & tools', then 'satellite imagery', then 'animated GIF' for either the Caribbean or Gulf of Mexico.

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NHC now has Delta as a 110 mph category 2 hurricane, and predicts it will strike the city of Cancun (pop. 750,000), in Mexico, as a 130 mph category 3 major hurricane tomorrow. Will weaken slightly afterwards before regaining strength to a 130 mph storm. However, conditions in the northern Gulf of Mexico aren't particularly supportive, so the landfall prediction in Louisiana is still 100 mph. They are excellent with track predictions, but not so much with intensity, tending to underestimate, rather than overestimate.

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The Copernicus satellite monitoring global temperature data is now in, and September was the warmest September on record, globally, at 0.05 C warmer than 2019, the previous record holder. Temperatures in Europe also set a new record, at 0.2 C warmer than 2018.

https://www.theguardian.com/environment/2020/oct/07/september-saw-hottest-temperatures-on-record-globally-and-in-europe

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