Some of the Effects of Global Warming

Californians face unprecedented fire blackouts in January, 2021

“In an unprecedented move, California utilities are warning they may need to cut power to more than 280,000 homes and businesses to prevent live wires from sparking wildfires as high winds are set to sweep through the drought-weary state.

Edison International’s Southern California Edison said 277,078 customers in multiple counties including Los Angeles face blackouts within 48 hours due to a forecast of a strong Santa Ana wind event. None of its customers that had been affected by earlier cuts are facing power outage as of Sunday afternoon, according to Southern California Edison’s website.

These power cuts are extremely rare in the winter and the utilities have never warned of a possible shutoff of this size in January. The blackouts planned this week could affect more than 800,000 people, based on the average size of the state’s households.

The unusual prospect of January shutoffs underscores how wild California’s weather has become as climate change brings about increasingly extreme warmth and drought. Last year, record temperatures took down large swaths of the state’s power grid and wildfires torched more acreage than ever before.

During a regular winter, public safety power shutoffs “would not be under consideration, but this winter has been anything but normal,” PG&E meteorologists said on the utility’s website. Only 22% of the average rainfall this winter has fallen in the southern Sierra, they said.

Some of the effects of global warming can be extremely counterintuitive

It has long been predicted by climate scientist that the Arctic would experience above average warming, due to positive feedback effects. However, no one predicted the consequences of this, which we’re now seeing.

The very cold polar air mass is held in place by the polar jet stream, which moves in a ‘wavy’, undulating manner, from west to east. The jet stream is a result of the temperature contrast between polar and sub polar air masses. As the Arctic has warmed more than the sub Arctic, the temperature contrast has diminished, resulting in a weakening of the jet stream. As a result, its giant ‘loops’, known as Rossby waves, have grown much larger, and are plunging further south than in the past.

This has resulted in both anomalously cold and anomalously warm winters in temperate latitude regions, depending on whether the region is getting the downswing (cold) or upswing (warm) of the loops. The polar vortex also often splits into two ‘lobes’, one going over North America, and the other over Siberia, binging very cold weather to both regions. The giant loops carry this cold air further south.

That was the set up in the UK during the ‘Beast from the East’ winter of 2018, and we’ve had a less extreme version of the beast from the east in recent weeks, which now seems to be relenting, as milder Atlantic weather fronts start to dominate the weather again. However, there could be a return to Arctic conditions by the end of the  month. Eastern Europe and the eastern Mediterranean are still trapped in the Arctic air flow, with -20 C recorded in Greece, and Athens blanketed in snow. Very unusual weather.

In North America, the plunging Rossby wave has brought record low temperatures as far south as Mexico. Record low temperatures rivalling the winters of 1899 and 1905 have been recorded in the US states of Minnesota, Nebraska, Iowa, South Dakota, Kansa, Wisconsin, Colorado, Missouri, Texas and Oklahoma, with emergency declarations in several states, as temperatures plummeted to -40 C, with wind chills of -60 C. The governor of Texas has issued a disaster declaration for all 254 counties. The temperature in Dallas fell to -15 C, and some 2.5 million households are currently without power. Most are heated with electricity. For comparison, hurricane Harvey resulted in 393,000 outages.

It’s a slowly unfolding disaster, with several days yet to run. One story I read was that of a mother and her young son in Texas, who tried to keep warm by getting into the car in the garage and turning the heating on. They died of carbon monoxide poisoning. Increased demand for electricity is a factor in the power cuts, but it seems that the main factor is that the power generating infrastructure has simply been crippled by the cold. Natural gas has frozen in the pipes, wind turbines have seized up, and even nuclear plants are unable to function normally.

At the same time, New York state is experiencing well above normal temperatures for the time of year, as it is influenced by the upswing of the jet stream loop returning north.

Methane Surge

We keep hearing about the impending ‘methane surge’, either from melting methane ice, mainly under the Arctic Ocean sea bed, or melting permafrost. Fact is, though, atmospheric methane was rising faster in the 80s, than it is today, and from about 1999 to 2007 it ‘flatlined’, with no significant increase.

Annual methane increase or decrease is far more erratic than CO2. Since 1984, the highest annual increase was 14.05 parts per billion (ppb) in 1991, and the smallest was a decrease of 4.88 ppb in 2004. No one knows why there are such annual discrepancies.

In the past year to November, the annual rise was 16.3 ppb. I don’t know if that’s a record for any 12 month period, and it might well just be a ‘blip’, given how erratic the annual methane increase/decrease is. On the other hand . . . .

https://www.esrl.noaa.gov/gmd/ccgg/trends_ch4/

Climate crisis: recent European droughts worst for 2,000 years

he series of severe droughts and heatwaves in Europe since 2014 is the most extreme for more than 2,000 years, research suggests.

The study analysed tree rings dating as far back as the Roman empire to create the longest such record to date. The scientists said global heating was the most probable cause of the recent rise in extreme heat.

The heatwaves have had devastating consequences, the researchers said, causing thousands of early deaths, destroying crops and igniting forest fires. Low river levels halted some shipping traffic and affected the cooling of nuclear power stations. Climate scientists predict more extreme and more frequent heatwaves and droughts in future.

The study also found a gradual drying of the summer climate in central Europe over the last two millennia, before the recent surge. The scientists ruled out volcanic activity and solar cycles as causes of this long-term trend and think subtle changes in Earth’s orbit are the cause.

“We’re all aware of the cluster of exceptionally hot and dry summers we’ve had over the past few years,” said Prof Ulf Büntgen, of Cambridge University, who led the study. “Our results show what we have experienced is extraordinary. The series is unprecedented for the last 2,000 years.” The available data ends in 2018, but 2019 and 2020 also had very hot European summers.

The scientists said changes in the position of the jet stream and the circulation of air over the continent caused the droughts, and that climate change was probably the underlying driver. “Climate change [means] extreme conditions will become more frequent, which could be devastating for agriculture, ecosystems and societies as a whole,” said Büntgen.

Prof Mrislav Trnka, of the CzechGlobe research centre in Brno, who was part of the study team, said the sharp increase in droughts was particularly alarming for agriculture and forestry. “Unprecedented forest dieback across much of central Europe corroborates our results,” he said.

https://www.theguardian.com/environment/2021/mar/15/climate-crisis-recent-european-droughts-worst-in-2000-years

March, 2021

Global Warming

This section: Science: Climate Change and Other Topics

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Avatar of PatByrne Publisher of Pat's Guide to Glasgow West End; the community guide to the West End of Glasgow. Fiction and non-fiction writer.

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