Showing posts with label Jennifer Francis. Show all posts
Showing posts with label Jennifer Francis. Show all posts

Monday, May 4, 2020

Very High Greenhouse Gas Levels

Carbon Dioxide

On June 1, 2020, NOAA recorded a daily average carbon dioxide (CO₂) level of 418.32 ppm at Mauna Loa, Hawaii.

The image below shows hourly average CO₂ levels approaching 419 ppm at Mauna Loa on May 1, 2020.
The image below shows hourly (red circles) and daily (yellow circles) averaged CO₂ values at Mauna Loa, Hawaii over 31 days, up to May 31, 2020, with some recent hourly averages showing up with values exceeding 419 ppm.
The image below shows hourly (red circles) and daily (yellow circles) averaged CO₂ values at Mauna Loa, Hawaii over 31 days, through June 1, 2020, when a daily average of 418.32 ppm was recorded.


By comparison, the highest daily average CO₂ level recorded by NOAA in 2019 at Mauna Loa was 415.64 ppm, as discussed in an earlier post. The image below shows how CO₂ growth has increased over the decades.

As illustrated by the image below, the daily average CO₂ on June 1, 2019, was 414.14 ppm and the daily average CO₂ on June 1, 2020, was 418.32 ppm, i.e. 4.18 ppm higher. The average in May 2019 was 414.65 ppm and the average in May 2020 was 417.07 ppm, i.e. 2.42 ppm higher. Since the annual maximum is typically reached in May, this high reading for June 1, 2020, could indicate that, while CO₂ emissions by people were suppressed in April and May 2020 due to the COVID-19 lockdowns, growth of CO₂ levels in the atmosphere continues to speed up now as restrictions are relaxed.


Even more significant than the daily averages could be the hourly averages. The daily average CO₂ level recorded by scripps.ucsd.edu at Mauna Loa, Hawaii, was 418.04 ppm on May 25, 2020. On May 24, 2020, one hourly average exceeded 420 ppm, at which time emissions by people had raised CO₂ levels by some 160 ppm compared to the situation thousands of years ago, and by even more if levels had continued to follow a natural trend, as illustrated by the image and inset below.


A rise of 100 ppm CO₂ has historically corresponded with a global temperature rise of some 10°C or 18°F, when looking at CO₂ levels and temperatures over the past 420,000 years, as illustrated by the image below.


Concentrations of carbon dioxide, methane (CH₄) and nitrous oxide (N₂O) in 2018 surged by higher amounts than during the past decade, according to a 2019 WMO news release and as illustrated by the image on the right, from an earlier post, which shows that CH₄, CO₂ and N₂O levels in the atmosphere in 2018 were, respectively, 259%, 147% and 123% of their pre-industrial (before 1750) levels.

So, methane levels have been rising much faster than CO₂ since 1750 and there is much potential for an even faster rise in methane levels due to seafloor hydrate releases.

Furthermore, as industrial activity declines in the wake of COVID-19, loss of aerosol masking alone could trigger a rapid rise, as discussed by Guy McPherson in recent papers here and here.

Given this, the 160 ppm rise in CO₂ could lead to a global temperature rise of 18°C or 32.4°F from 1750, and such a rise could unfold soon, as oceans and ice take up ever less heat and further feedbacks kick in, as also discussed in earlier post such as this one and this one.

Levels for methane and nitrous oxide were very high in May 2020, as further discussed below.

Methane

MetOp-1 recorded peak methane levels of 2917 ppb at 469 mb on the afternoon of May 22, 2020.


MetOp-1 recorded mean methane levels of 1896 ppb at 336 mb on the morning of May 22, 2020.


MetOp-2 recorded peak methane levels of 1918 ppb at 586 mb on the afternoon of May 24, 2020.


Nitrous Oxide

N20 recorded peak nitrous oxide levels of 366 ppb at 840 mb on the morning of May 21, 2020.


N20 recorded somewhat lower peak nitrous oxide levels of 346.9 ppb at 487.2 mb on the afternoon of May 23, 2020, but look at how much of Antarctica is covered by the magenta color, reflecting levels at the top end of the scale.


Rising greenhouse gas levels are damaging the ozone layer

Nitrous oxide is both a potent greenhouse gas and an ozone depleting substance that is thus directly damaging the ozone layer.

Additionally, rising greenhouse gas levels are indirectly damaging the ozone layer in three ways:

Firstly, rising greenhouse gas levels are making water vapor enter the stratosphere. Higher sea surface temperatures along the path of the Gulf Stream fuel hurricanes traveling north along North America's east coast. More heat also translates into more wind; stronger hurricanes are getting stronger over the years.

Rising levels of greenhouse gases strengthen winds and increase water vapor in the atmosphere. Temperatures are rising faster in the Arctic than in the rest of the world, as illustrated by the image below, and this is changing the Jet Stream.

[ click on images to enlarge ]
Jennifer Francis has long pointed out that, as temperatures at the North Pole are rising faster than at the Equator, the Jet Stream is becoming wavier and can get stuck in a 'blocking pattern' for days, increasing the duration and intensity of extreme weather events. This can result in stronger storms moving more water vapor inland over the U.S., as discussed in earlier posts such as this one. Such storms can cause large amounts of water vapor to rise high up in the sky. Water vapor that enters the stratosphere can damage the ozone layer.

Secondly, as plumes above the anvils of severe storms bring water vapor up into the stratosphere, this also contributes to the formation of cirrus clouds that trap a lot of heat that would otherwise be radiated away, from Earth into space.

Thirdly, higher temperatures and stronger winds increase the intensity of droughts. Heatwaves combined with strong winds, dry soil and dry vegetation can make forest fires produce smoke that can enter the stratosphere and stay there for along time.

Recent examples of extreme weather events are described below, i.e. a huge storm and a heatwave in the Arctic.

Super Typhoon Amphan hits India and Bangladesh

Also in May 2020, super typhoon Amphan hit India and Bangladesh, with high waves and heavy rainfall. Waves as high as 14.2 m or 46.6 ft were forecast (at the green circle) for May 20, 2020, 06:00 UTC as Amphan approached Bangladesh.

"Once once-in-a-century, now once-in-a-decade", comments Sam Carana on this and other events.


The sea surface temperature image below shows that, on May 17, 2020, ocean temperatures were as high as 32.9°C or 91.1°F.


The combination image below shows high sea surface temperatures on May 15, 2020, 12:00 UTC, in the left panel.


Anomalies in the Indian Ocean were as high as 3.4°C or 6.0°F, in the Arctic Ocean as high as 1°C or 1.8°F and in the Pacific Ocean as high as 5.1°C or 9.1°F. Anomalies are from daily average during years 1981-2011.

The right panel of the combination image shows how these high ocean temperatures cause circular wind patterns. Wind speed was as high as 255 km/h or 159 mph in the Indian Ocean, at the location of super typhoon Amphan, on May 18, 2020, 06:00 UTC, while instantaneous wind power density was as high as 177.2 kW/m².

The combination image below shows the temporary cooling impact of Amphan.


The bottom panel shows that on May 18, 2020 09:00 UTC, the temperature at a location in India was 42.6°C or 108.6°F, as Amphan was approaching from the South.

The middle panel shows that, two days later, at the same location and at same time of day, the temperature had fallen to 23.4°C or 74°F as Amphan hit the area.

The cooling is only temporary. The top panel shows that a temperature of 47.9°C or 118.1°F is forecast for that location, same time of day, for May 26, 2020.

Siberian Heatwave

A heatwave hit Siberia in May 2020.


Above image shows that temperature anomalies were forecast to be at the high end of the scale over Siberia on May 22, 2020, 06:00 UTC, i.e. 30°C or 54°F higher than 1979-2000. At the same time, cold temperatures are forecast for much of eastern Europe.

What enables such a strong heatwave to develop is that the Jet Stream is getting more wavy as the temperature difference between the North Pole and the Equator is narrowing, causing both hot air to move up into the Arctic (red arrow) and cold air to descend out of the Arctic (blue arrow).

The Siberian heatwave threatens to trigger forest fires that can cause large amounts of black carbon to settle on the snow and ice cover, speeding up its demise. Furthermore, the heatwave threatens rivers to heat up that carry large amounts of water into the Arctic Ocean. Finally, as discussed, more intense forest fires threaten to cause organic carbon compounds to enter the stratosphere.

Extinction mechanism

A recent study by John Marshall et al. found that the Devionian mass extinction event 360 million years ago, that killed much of the Earth's plant and freshwater aquatic life, was caused by a brief breakdown of the ozone layer. John Marshall says: "Current estimates suggest we will reach similar global temperatures to those of 360 million years ago, with the possibility that a similar collapse of the ozone layer could occur again, exposing surface and shallow sea life to deadly radiation. This would move us from the current state of climate change, to a climate emergency."

John refers to the work by James Anderson et al., who warn that CO₂ and CH₄ release from clathrates and permafrost could cause more water to get carried into the stratosphere. John further describes the 'Extinction mechanism': "High summer temperatures over continental areas can increase the transport of water vapour high into the atmosphere. This water vapour carries with it organic carbon compounds that include chlorine, which are produced naturally by a wide variety of plants, algae and fungi. Once these compounds are near the ozone layer, they release the chlorine and this breaks down ozone molecules. This produces a positive feedback loop because a collapsing terrestrial ecosystem will release a flush of nutrients into the oceans, which can cause a rapid increase in algae."

Arctic sea ice volume

As Guy McPherson points out, COVID-19 alone could trigger an abrupt huge temperature rise.

Furthermore, loss of Arctic sea ice could cause a rapid temperature rise.

Ominously, Arctic sea ice volume has been at record low since the start of 2020, while 2019 volume was at a record low from October, making that volume has now been at record low for almost 8 months straight.

The situation is dire and calls for immediate, comprehensive and effective action as described in the Climate Plan.


Links

• Climate Plan
https://arctic-news.blogspot.com/p/climateplan.html

• Climate Plan (June 1, 2019 version)
https://arctic-news.blogspot.com/2019/06/climate-plan.html

• The Keeling Curve - Scripps Institution of Oceanography at UC San Diego
https://scripps.ucsd.edu/programs/keelingcurve

• 417.93 parts per million (ppm) CO2 in air 24-May-2020
https://twitter.com/Keeling_curve/status/1264955470655025152

• Greenhouse Gas Levels Keep Accelerating
https://arctic-news.blogspot.com/2019/05/greenhouse-gas-levels-keep-accelerating.html

• Will COVID-19 Trigger Extinction of All Life on Earth? - by Guy McPherson
https://opastonline.com/wp-content/uploads/2020/04/will-covid-19-trigger-extinction-of-all-life-on-earth-eesrr-20-.pdf

• Earth is in the Midst of Abrupt, Irreversible Climate Change - by Guy McPherson
https://www.onlinescientificresearch.com/articles/earth-is-in-the-midst-of-abrupt-irreversible-climate-change.pdf

• Extinction
https://arctic-news.blogspot.com/p/extinction.html

• Most Important Message Ever
https://arctic-news.blogspot.com/2019/07/most-important-message-ever.html

• Methane
https://arctic-news.blogspot.com/p/methane.html

• Study shows erosion of ozone layer responsible for mass extinction event
https://www.eurekalert.org/pub_releases/2020-05/uos-sse052620.php

• UV-B radiation was the Devonian-Carboniferous boundary terrestrial extinction kill mechanism - by John Marshall et al.
https://advances.sciencemag.org/content/6/22/eaba0768

• Prehistoric climate change damaged the ozone layer and led to a mass extinction - by John Marshall
https://theconversation.com/prehistoric-climate-change-damaged-the-ozone-layer-and-led-to-a-mass-extinction-139519

• UV Dosage Levels in Summer: Increased Risk of Ozone Loss from Convectively Injected Water Vapor - by James Anderson et al.
https://science.sciencemag.org/content/337/6096/835

• Care for the Ozone Layer
https://arctic-news.blogspot.com/2019/01/care-for-the-ozone-layer.html

• Why stronger winds over the North Atlantic are so dangerous
https://arctic-news.blogspot.com/2020/02/why-stronger-winds-over-north-atlantic-are-so-dangerous.html

• A Global Temperature Rise Of More than Ten Degrees Celsius By 2026?
https://arctic-news.blogspot.com/2016/07/a-global-temperature-rise-of-more-than-ten-degrees-celsius-by-2026.html

• Forces behind Superstorm Sandy
https://arctic-news.blogspot.com/2012/11/forces-behind-superstorm-sandy.html

• April 2020 temperatures very high
https://arctic-news.blogspot.com/2020/05/april-2020-temperatures-very-high.html

• Could Humans Go Extinct Within Years?
https://arctic-news.blogspot.com/2020/01/could-humans-go-extinct-within-years.html

• Arctic Ocean November 2019
https://arctic-news.blogspot.com/2019/11/arctic-ocean-november-2019.html






Friday, February 1, 2019

How frigid polar vortex blasts are connected to global warming

by Jennifer Francis, Rutgers University

File 20190128 39344 1rjndrb.jpg?ixlib=rb 1.1
Bundled up against the cold in downtown Chicago, Sunday, Jan. 27, 2019.
AP Photo/Nam Y. Huh

A record-breaking cold wave is sending literal shivers down the spines of millions of Americans. Temperatures across the upper Midwest are forecast to fall an astonishing 50 degrees Fahrenheit (28 degrees Celsius) below normal this week – as low as 35 degrees below zero. Pile a gusty wind on top, and the air will feel like -60 F.



Predicted near-surface air temperatures (F) for Wednesday morning, Jan. 30, 2019. Forecast by NOAA’s Global Forecast System model. Pivotal Weather, CC BY-ND
This cold is nothing to sneeze at. The National Weather Service is warning of brutal, life-threatening conditions. Frostbite will strike fast on any exposed skin. At the same time, the North Pole is facing a heat wave with temperatures approaching the freezing point – about 25 degrees Fahrenheit (14 C) above normal.




Predicted near-surface air temperature differences (C) from normal, relative to 1981-2010.
Pivotal Weather, CC BY-ND
What is causing this topsy-turvy pattern? You guessed it: the polar vortex.

In the past several years, thanks to previous cold waves, the polar vortex has become entrenched in our everyday vocabulary and served as a butt of jokes for late-night TV hosts and politicians. But what is it really? Is it escaping from its usual Arctic haunts more often? And a question that looms large in my work: How does global warming fit into the story?



Jimmy Fallon examines the pros and cons of the polar vortex.

Rivers of air

Actually, there are two polar vortices in the Northern Hemisphere, stacked on top of each other. The lower one is usually and more accurately called the jet stream. It’s a meandering river of strong westerly winds around the Northern Hemisphere, about seven miles above Earth’s surface, near the height where jets fly.

The jet stream exists all year, and is responsible for creating and steering the high- and low-pressure systems that bring us our day-to-day weather: storms and blue skies, warm and cold spells. Way above the jet stream, around 30 miles above the Earth, is the stratospheric polar vortex. This river of wind also rings the North Pole, but only forms during winter, and is usually fairly circular.



Dark arrows indicate rotation of the polar vortex in the Arctic; light arrows indicate the location of the polar jet stream when meanders form and cold, Arctic air dips down to mid-latitudes. L.S. Gardiner/UCAR, CC BY-ND
Both of these wind features exist because of the large temperature difference between the cold Arctic and warmer areas farther south, known as the mid-latitudes. Uneven heating creates pressure differences, and air flows from high-pressure to low-pressure areas, creating winds. The spinning Earth then turns winds to the right in the northern hemisphere, creating these belts of westerlies.

Why cold air plunges south

Greenhouse gas emissions from human activities have warmed the globe by about 1.8 degrees Fahrenheit (1 C) over the past 50 years. However, the Arctic has warmed more than twice as much. Amplified Arctic warming is due mainly to dramatic melting of ice and snow in recent decades, which exposes darker ocean and land surfaces that absorb a lot more of the sun’s heat.

Because of rapid Arctic warming, the north/south temperature difference has diminished. This reduces pressure differences between the Arctic and mid-latitudes, weakening jet stream winds. And just as slow-moving rivers typically take a winding route, a slower-flowing jet stream tends to meander.

Large north/south undulations in the jet stream generate wave energy in the atmosphere. If they are wavy and persistent enough, the energy can travel upward and disrupt the stratospheric polar vortex. Sometimes this upper vortex becomes so distorted that it splits into two or more swirling eddies.

These “daughter” vortices tend to wander southward, bringing their very cold air with them and leaving behind a warmer-than-normal Arctic. One of these eddies will sit over North America this week, delivering bone-chilling temperatures to much of the nation.

Deep freezes in a warming world

Splits in the stratospheric polar vortex do happen naturally, but should we expect to see them more often thanks to climate change and rapid Arctic warming? It is possible that these cold intrusions could become a more regular winter story. This is a hot research topic and is by no means settled, but a handful of studies offer compelling evidence that the stratospheric polar vortex is changing, and that this trend can explain bouts of unusually cold winter weather.

Undoubtedly this new polar vortex attack will unleash fresh claims that global warming is a hoax. But this ridiculous notion can be quickly dispelled with a look at predicted temperature departures around the globe for early this week. The lobe of cold air over North America is far outweighed by areas elsewhere in the United States and worldwide that are warmer than normal.



Predicted daily mean, near-surface temperature (C) differences from normal (relative to 1979-2000) for Jan. 28-30, 2019. Data from NOAA’s Global Forecast System model.
Climate Reanalyzer, Climate Change Institute, University of Maine., CC BY-ND
Symptoms of a changing climate are not always obvious or easy to understand, but their causes and future behaviors are increasingly coming into focus. And it’s clear that at times, coping with global warming means arming ourselves with extra scarfs, mittens and long underwear.

Jennifer Francis, Visiting Professor, Rutgers University

This article is republished from The Conversation under a Creative Commons license. Read the original article.


Sunday, January 20, 2019

Care for the Ozone Layer


The stratosphere normally is cold and very dry. Global warming can increase water vapor in the stratosphere in a number of ways. Global warming causes the troposphere to warm and since warmer air holds more water vapor, the amount of water vapor in the troposphere is increasing. This can cause more water vapor to end up in the stratosphere as well, as described below.

Stratospheric Water Vapor over the Arctic

Around the time of the December Solstice, very little sunlight is reaching the Arctic and temperatures over land at higher latitudes can get very low. At the same time, global warming has made oceans warmer and this keeps air temperatures over water relatively warm in Winter. This can lead to a number of phenomena including sudden stratospheric warming and moistening of the stratosphere.

Sudden stratospheric warming is illustrated by the image on the right, showing temperatures in the stratosphere over Siberia as high as 12.7°C or 54.9°F on December 24, 2018, and temperatures as low as -84.8°C or -120.6°F over Greenland.

At the same time, relative humidity was as high as 100% in the stratosphere over the North Sea, as the second image on the right shows.

Moistening of the stratosphere was even more pronounced on December 24, 2016, as illustrated by the third image on the right.

Storms over the U.S.

Jennifer Francis has long pointed out that, as temperatures at the North Pole are rising faster than at the Equator, the Jet Stream is becoming wavier and can get stuck in a 'blocking pattern' for days, increasing the duration and intensity of extreme weather events.

This can result in stronger storms moving more water vapor inland over the U.S., and such storms can cause large amounts of water vapor to rise high up in the sky.

Water vapor reaching stratospheric altitudes causes loss of ozone, as James Anderson describes in a 2017 paper and discusses in the short 2016 video below.


Methane

Stratospheric water vapor can also result from methane oxidation in the stratosphere. Methane concentrations have risen strongly at higher altitudes over the years. Noctilucent clouds indicate that methane has led to water vapor in the upper atmosphere.

The danger is that, as the Arctic Ocean keeps warming, large eruptions of methane will occur from the seafloor. Ominously, high methane levels have recently shown up on satellite images over the Arctic at lower altitudes, indicating the methane is escaping from the sea.

The images below show methane levels recorded by the NPP satellite:
Jan. 6, 2019, with peak levels of 2513 ppb at 1000 mb, 2600 ppb at 840 mb and 2618 ppb at 695 mb;
Jan. 11, 2019, with peak levels of 2577 ppb at 1000 mb, 2744 ppb at 840 mb and 2912 ppb at 695 mb;
Jan. 15, 2019, with peak levels of 2524 ppb at 1000 mb, 2697 ppb at 840 mb and 2847 ppb at 695 mb.

















The images below show methane levels recorded by the MetOp satellites:
Jan. 15, 2019, with peak levels of 2177 ppb at 840 mb, 2342 ppb at 695 mb and 2541 ppb at 586 mb;
Jan. 16, 2019, with peak levels of 2219 ppb at 840 mb, 2299 ppb at 695 mb and 2475 ppb at 586 mb;
Jan. 19, 2019, with peak levels of 2201 ppb at 840 mb, 2489 ppb at 695 mb and 2813 ppb at 586 mb.
















The Importance of the Ozone Layer

Increases in stratospheric water vapor are bad news, as they speed up global warming and lead to loss of stratospheric ozone, as Drew Shindell pointed out back in 2001.

It has long been known that deterioration of the ozone shield increases ultraviolet-B irradiation, in turn causing skin cancer. Recent research suggest that, millions of years ago, it could also have led to loss of fertility and consequent extinction in plants and animals (see box right).

Nitrous oxide

As the left panel of the image below shows, growth in the levels of chlorofluorocarbons (CFCs) has slowed over the years, but their impact will continue for a long time, given their long atmospheric lifetime (55 years for CFC-11 and 140 years for CFC-12, CCl2F2).

Furthermore, as the right panel shows, the impact of nitrous oxide (N₂O) as an ozone depleting substance (ODS) has relatively grown, while N₂O levels also continue to increase in the atmosphere.

[ click on images to enlarge ]
Existential Threats

In conclusion, rising levels of emissions by people constitute existential threats in many ways. Rising temperatures cause heat stress and infertility, and there are domino effects. Furthermore, stratospheric ozone loss causes cancer and infertility.

Only once the ozone layer formed on Earth some 600 million years ago could multicellular life develop and survive. Further loss of stratospheric ozone could be the fastest path to extinction for humanity, making care for the ozone layer imperative.

As described in an earlier post, Earth is on the edge of runaway warming and in a moist-greenhouse scenario oceans evaporate into the stratosphere with loss of the ozone layer.

The situation is dire and calls for comprehensive and effective action, as described in the Climate Plan.


Links

• Climate and ozone response to increased stratospheric water vapor, by Drew Shindell (2001)
https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/1999GL011197

• Stratospheric ozone over the United States in summer linked to observations of convection and temperature via chlorine and bromine catalysis, by James Anderson et al. (2017)
https://www.pnas.org/content/114/25/E4905

• Harvard Speaks on Climate Change: James Anderson (2016)
https://vimeo.com/185794598

• Climate Week: Climate Science Breakfast with James Anderson (April 9, 2015)
http://environment.harvard.edu/climate-week-climate-science-breakfast-james-anderson

• 10°C or 18°F warmer by 2021?
https://arctic-news.blogspot.com/2017/04/10c-or-18f-warmer-by-2021.html

• Noctilucent clouds indicate more methane in upper atmosphere
https://arctic-news.blogspot.com/2012/09/noctilucent-clouds-indicate-more-methane-in-upper-atmosphere.html

• Noctilucent clouds: further confirmation of large methane releases
https://methane-hydrates.blogspot.com/2013/12/noctilucent-clouds-further-confirmation-of-large-methane-releases.html

• It could be unbearably hot in many places within a few years time
https://arctic-news.blogspot.com/2016/07/it-could-be-unbearably-hot-in-many-places-within-a-few-years-time.html

• Climate change: effect on sperm could hold key to species extinction, by Kris Sales
https://theconversation.com/climate-change-effect-on-sperm-could-hold-key-to-species-extinction-107375

• Climate change: effect on sperm could hold key to species extinction
https://theconversation.com/climate-change-effect-on-sperm-could-hold-key-to-species-extinction-107375

• UV-B–induced forest sterility: Implications of ozone shield failure in Earth’s largest extinction, by Jeffrey Benca et al. (2018)
http://advances.sciencemag.org/content/4/2/e1700618

• Co-extinctions annihilate planetary life during extreme environmental change, by Giovanni Strona and Corey Bradshaw (2018)
https://www.nature.com/articles/s41598-018-35068-1

• NOAA's Annual Greenhouse Gas Index
https://www.esrl.noaa.gov/gmd/aggi

• NOAA Study Shows Nitrous Oxide Now Top Ozone-Depleting Emission
https://www.esrl.noaa.gov/news/2009/nitrous_oxide_top_ozone_depleting_gas.html

• Earth is on the edge of runaway warming
https://arctic-news.blogspot.com/2013/04/earth-is-on-the-edge-of-runaway-warming.html

• Climate Plan
https://arctic-news.blogspot.com/p/climateplan.html



Saturday, February 3, 2018

Is warming in the Arctic behind this year's crazy winter weather?

Is warming in the Arctic behind this year's crazy winter weather?

File 20180111 101511 sa3hd1.jpg?ixlib=rb 1.1
Seriously cold: The ‘bomb cyclone’ freezes a fountain in New York City.
AP Photo/Mark Lennihan
Jennifer Francis, Rutgers University

Damage from extreme weather events during 2017 racked up the biggest-ever bills for the U.S. Most of these events involved conditions that align intuitively with global warming: heat records, drought, wildfires, coastal flooding, hurricane damage and heavy rainfall.

Paradoxical, though, are possible ties between climate change and the recent spate of frigid weeks in eastern North America. A very new and “hot topic” in climate change research is the notion that rapid warming and wholesale melting of the Arctic may be playing a role in causing persistent cold spells.

It doesn’t take a stretch of the imagination to suppose that losing half the Arctic sea-ice cover in only 30 years might be wreaking havoc with the weather, but exactly how is not yet clear. As a research atmospheric scientist, I study how warming in the Arctic is affecting temperature regions around the world. Can we say changes to the Arctic driven by global warming have had a role in the freakish winter weather North America has experienced?

A ‘dipole’ of abnormal temperatures

Weird and destructive weather was in the news almost constantly during 2017, and 2018 seems to be following the same script. Most U.S. Easterners shivered their way through the end of 2017 into the New Year, while Westerners longed for rain to dampen parched soils and extinguish wildfires. Blizzards have plagued the Eastern Seaboard – notably the “bomb cyclone” storm on Jan. 4, 2018 – while California’s Sierra Nevada stand nearly bare of snow.
A study in contrasts: Warming near Alaska and the Pacific Ocean are ‘ingredients’ to a weather pattern where cold air from the Arctic plunges deep into North America.
NASA Earth Observatory, CC BY
This story is becoming a familiar one, as similar conditions have played out in four of the past five winters. Some politicians in Washington D.C., including President Trump, have used the unusual cold to question global warming. But if they looked at the big picture, they’d see that eastern cold spells are a relative fluke in the Northern Hemisphere as a whole and that most areas are warmer than normal.

A warm, dry western North America occurring in combination with a cold, snowy east is not unusual, but the prevalence and persistence of this pattern in recent years have piqued the interests of climate researchers.

The jet stream – a fast, upper-level river of wind that encircles the Northern Hemisphere – plays a critical role. When the jet stream swoops far north and south in a big wave, extreme conditions can result. During the past few weeks, a big swing northward, forming what’s called a “ridge” of persistent atmospheric pressure, persisted off the West Coast along with a deep southward dip, or a “trough,” over the East.

New terms have been coined to describe these stubborn features: “The North American Winter Temperature Dipole,” the “Ridiculously Resilient Ridge” over the West, and the “Terribly Tenacious Trough” in the East.
While the eastern U.S. suffered very cold temperatures in the recent cold snap, much of the rest of the Northern Hemisphere saw higher-than-average air temperatures.
NOAA, CC BY

Regardless what it’s called, this dipole pattern – abnormally high temperatures over much of the West along with chilly conditions in the East – has dominated North American weather in four of the past five winters. January 2017 was a stark exception, when a strong El Niño flipped the ridge-trough pattern, dumping record-breaking rain and snowpack on California while the east enjoyed a mild month.

Two other important features are conspicuous in the dipole temperature pattern: extremely warm temperatures in the Arctic near Alaska and warm ocean temperatures in the eastern Pacific. Several new studies point to these “ingredients” as key to the recent years with a persistent dipole.

It takes two to tango

What role does warming – specifically the warming ocean and air temperatures in the Arctic – play in this warm-West/cool-East weather pattern? The explanation goes like this.

Pacific Ocean temperatures fluctuate naturally owing to short-lived phenomena such as El Niño/La Niña and longer, decades-length patterns. Scientists have long recognized that those variations affect weather patterns across North America and beyond.
When a persistent area of atmospheric pressure stays in the western U.S., air from the Arctic pours into the U.S, causing a split between the warm and dry West and the cold East.
Mesocyclone2014 and David Swain, CC BY-SA

The new twist in this story is that the Arctic has been warming at at least double the pace of the rest of the globe, meaning that the difference in temperature between the Arctic and areas farther south has been shrinking. This matters because the north/south temperature difference is one of the main drivers of the jet stream. The jet stream creates the high- and low-pressure systems that dictate our blue skies and storminess while also steering them. Anything that affects the jet stream will also affect our weather.

When ocean temperatures off the West Coast of North America are warmer than normal, as they have been most of the time since winter 2013, the jet stream tends to form a ridge of high pressure along the West Coast, causing storms to be diverted away from California and leaving much of the West high and dry.

If these warm ocean temperatures occur in combination with abnormally warm conditions near Alaska, the extra heat from the Arctic can intensify the ridge, causing it to reach farther northward, become more persistent, and pump even more heat into the region near Alaska. And in recent years, Alaska has experienced periods of record warm temperatures, owing in part to reduced sea ice.

My colleagues and I have called this combination of natural and climate change-related effects “It Takes Two to Tango,” a concept that may help explain the Ridiculously Resilient Ridge observed frequently since 2013. Several new studies support this human-caused boost of a natural pattern, though controversy still exists regarding the mechanisms linking rapid Arctic warming with weather patterns farther south in the mid-latitudes.

More extreme weather ahead?

In response to the strengthened western ridge of atmospheric pressure, the winds of the jet stream usually also form a deeper, stronger trough downstream. Deep troughs act like an open refrigerator door, allowing frigid Arctic air to plunge southward, bringing misery to areas ill-prepared to handle it. Snowstorms in Texas, ice storms in Georgia and chilly snowbirds in Florida can all be blamed on the Terribly Tenacious Trough of December 2017 and January 2018.
Cold weather from the Arctic combined with warm tropical air fueled a storm that produced well over a foot of snow and spots of flooding in Boston.
AP Photo/Michael Dwyer
Adding icing on the cake is the tendency for so-called “nor’easters,” such as the “bomb cyclone” that struck on Jan. 4, to form along the East Coast when the trough’s southwest winds align along the Atlantic Seaboard. The resulting intense contrast in temperature between the cold land and Gulf Stream-warmed ocean provides the fuel for these ferocious storms.

The big question is whether climate change will make dipole patterns – along with their attendant tendencies to produce extreme weather – more common in the future. The answer is yes and no.

It is widely expected that global warming will produce fewer low-temperature records, a tendency already observed. But it may also be true that cold spells will become more persistent as dipole patterns intensify, a tendency that also seems to be occurring.

It’s hard to nail down whether this weather pattern – overall warmer winters in North America but longer cold snaps – will persist. Understanding the mechanisms behind these complex interactions between natural influences and human-caused changes is challenging.

The ConversationNevertheless, research is moving forward rapidly as creative new metrics are developed. Our best tools for looking into the future are sophisticated computer programs, but they, too, struggle to simulate these complicated behaviors of the climate system. Given the importance of predicting extreme weather and its impacts on many aspects of our lives, researchers must continue to unravel connections between climate change and weather to help us prepare for the likely ongoing tantrums by Mother Nature.

Jennifer Francis, Research Professor, Rutgers University

This article was originally published on The Conversation. Read the original article.

Monday, October 2, 2017

The Arctic is Changing the Jet Stream - Why This Is Important

By Sam Carana, with contributions by Jennifer Francis

Global warming is increasing the strength of hurricanes. A warmer atmosphere holds more water vapor and sea surface temperatures are rising. Both of these changes strengthen hurricanes. Steering winds may also be changing, causing unusual hurricane tracks such as Sandy's left turn into the mid-Atlantic seaboard and Harvey's stagnation over Houston. Is rapid Arctic warming playing a role?

Jennifer Francis has long been warning that global warming is increasing the likelihood of wavier jet stream patterns and more frequent blocking events, both of which have been observed. The Arctic is warming more rapidly than the rest of the world. The narrowing temperature difference between the Arctic and lower latitudes is weakening the speed at which the jet stream circumnavigates Earth and may be making the jet stream more wavy. In a 2012 study, Jennifer Francis and Stephen Vavrus warned that this makes atmospheric blocking events in the Northern Hemisphere more likely, aggravating extreme weather events related to stagnant weather conditions, such as drought, flooding, cold spells, and heat waves.

The danger was highlighted later that year, when a strong block associated with a deep jet stream trough helped steered Hurricane Sandy toward New York. In 2017, Hurricane Harvey hovered over Houston and dumped record-breaking rains (over 50 inches in some locations!), again highlighting this danger.

The jet stream separates cold air in the Arctic from warmer air farther south. A wavier jet stream transports more heat and moisture into the Arctic. This speeds up warming of the Arctic in a number of ways. In addition to warming caused by the extra heat, the added water vapor is a potent greenhouse gas, trapping more heat in the atmosphere over the Arctic, while it also causes more clouds to form that also are effective heat trappers.

As the Arctic keeps warming, the jet stream is expected to become more distorted, bringing ever more heat and moisture into the Arctic. This constitutes a self-reinforcing feedback loop that keeps making the situation worse. In conclusion, it's high time for more comprehensive and effective action to reduce the underlying culprit: global warming.


Jennifer Francis is Research Professor at the Institute of Marine and Coastal Sciences at Rutgers University, where she studies Arctic climate change and the link between the Arctic and global climates.

Jennifer has received funding from the National Science Foundation and NASA. She is a member of the American Meteorological Society, American Geophysical Union, Association for Women in Science and the Union of Concerned Scientists.


Links

• Evidence Linking Arctic Amplification to Extreme Weather in Mid-Latitudes, by Jennifer Francis and Stephen Vavrus (March 17, 2012)
http://onlinelibrary.wiley.com/doi/10.1029/2012GL051000/full

• Why Are Arctic Linkages to Extreme Weather Still Up in the Air? By Jennifer Francis (July 7, 2017)
http://journals.ametsoc.org/doi/abs/10.1175/BAMS-D-17-0006.1

• Amplified Arctic warming and mid‐latitude weather: new perspectives on emerging connections, by Jennifer Francis, Stephen Vavrus, Judah Cohen (May 16, 2017)
http://wires.wiley.com/WileyCDA/WiresArticle/wisId-WCC474.html

• Jennifer Francis: A New Arctic Feedback - Dec 2016 interview with Peter Sinclair (Jan 16, 2017)
https://www.youtube.com/watch?v=w_EzF4k9_QY

• Precipitation over the Arctic - by Sam Carana (27 Jan 2017)
https://www.youtube.com/watch?v=R_q3uWQR8Mw

• Jennifer Francis - Understanding the jet stream (26 Feb 2013)
https://www.youtube.com/watch?v=_nzwJg4Ebzo



Friday, January 27, 2017

Arctic Ocean Feedbacks


The world is warming rapidly, and the Arctic is warming much more rapidly than the rest of the world. In December 2016, the temperature anomaly from latitude 83°N to the North Pole was 8 times as high as the global anomaly. Above forecast for February 6, 2017, shows that temperatures over parts of the Arctic Ocean will be as much as 30°C or 54°F higher than they were in 1979-2000. How can it be so much warmer in a place where, at this time of year, little or no sunlight is shining? The Arctic Ocean is warming particularly rapidly due to a multitude of feedbacks, some of which are illustrated on the image below.


As the Arctic is warming more rapidly than the rest of the world, the temperature difference between the Arctic and the northern latitudes decreases, which makes the jet stream wavier. Jennifer Francis has written extensively about jet stream changes as a result of rapid warming in the Arctic. In the video below, Peter Sinclair interviews Jennifer Francis on these changes.


The changes to the jet stream make it easier for warm air from the south to enter the Arctic and for cold air to move out of the Arctic deep down into North America and Eurasia. At the same time, this also increases the temperature difference between the continents and the oceans, which is quite significant given the rapid warming of oceans across the globe. The result of the greater temperature difference between oceans and continents is that stronger winds are now flowing over the oceans along the jet stream tracks.

Stronger winds come with more evaporation and rain, which accumulates as freshwater at the surface of the North Atlantic and the North Pacific. The freshwater acts as a seal, as a lid on the ocean, making that less heat gets transferred from underneath the freshwater lid to the atmosphere. This makes that more heat can travel underneath the sea surface through the North Atlantic and reach the Arctic Ocean.


On January 28, 2017, sea surface temperature anomalies as high as 18.4°C (or 33.1°F) were showing up off the coast of Japan.


The situation is illustrated by above images, showing areas over the North Atlantic and the North Pacific (blue) where the sea surface was colder than it was in 1981-2011. Over these colder areas, winds are stronger due to the changes to the jet stream. On January 28, 2017, temperature anomalies were as high as 18.4°C (or 33.1°F) off the coast of Japan, while temperature anomalies were as high as 10.9°C (or 19.5°F) near Svalbard in the Arctic on January 27, 2017.

The image on the right shows sea surface temperature anomalies from 1971-2000.

The video below shows precipitation over the Arctic, run on January 27, 2017, and valid up to February 4, 2017.


Beaufort Gyre and Transpolar Drift
Changes to wind patterns can also affect sea currents in the Arctic Ocean such as the Beaufort Gyre and the Transpolar Drift. In the video below, at around 7:00, Paul Beckwith warns that further loss of sea ice will make these sea currents change direction, which in turn will draw more warm seawater from the North Atlantic into the Arctic Ocean.

As more ocean heat enters the Arctic Ocean and as sea ice retreats, more heat and water vapor will rise from the Arctic Ocean into the atmosphere over the Arctic. Increased water vapor will make it harder for heat to escape into space, i.e. more heat will remain trapped in the atmosphere and this will add to global warming.


The changes to the jet stream and the associated changes discussed above all lead to further warming of the Arctic Ocean, next to the warming caused by other feedbacks such as loss of albedo and loss of ice as a heat buffer. Together, sea ice loss and these associated feedbacks could cause global temperatures to rise by 1.6°C by 2026.

There are further feedbacks affecting the Arctic, as described at this page. One of the most dangerous feedbacks is methane escaping from the seafloor of the Arctic Ocean. As the temperature of the Arctic Ocean keeps rising, it seems inevitable that more and more methane will rise from its seafloor and enter the atmosphere, at first strongly warming up the atmosphere over the Arctic Ocean itself - thus causing further methane eruptions - and eventually warming up the atmosphere across the globe.

Above image paints a dire warning. The image shows that methane levels were as high as 2562 ppb on January 28, 2017. The image further shows high methane levels off the coast of Siberia and also where water from Nares Strait enters Baffin Bay.

Feedbacks and further elements of a potential temperature rise by 2026 of more than 10°C above prehistoric levels are further described at the extinction page.

The situation is dire and calls for comprehensive and effective action as described in the Climate Plan.


Links

• Climate Plan
http://arctic-news.blogspot.com/p/climateplan.html

• Feedbacks
http://arctic-news.blogspot.com/p/feedbacks.html

• Extinction
http://arctic-news.blogspot.com/p/extinction.html

• 2016 well above 1.5°C
http://arctic-news.blogspot.com/2017/01/2016-well-above-1.5c.html

• Accelerating Warming of the Arctic Ocean
http://arctic-news.blogspot.com/2016/12/accelerating-warming-of-the-arctic-ocean.html


Saturday, November 22, 2014

How melting Arctic ice is driving harsh winters

by Nick Breeze

The very least 'global warming' could do for us is to give us warmer winters, right? Wrong, writes Nick Breeze, who met climate scientist and meteorologist Jennifer Francis in his attempt to understand the complex interactions of jet stream, polar vortex, the melting Arctic, and the extreme snowfall that's hitting the northeast US right now.

"Historic" snowfalls have the US northeast this week, with Buffalo, New York under an astonishing 2.4m (8ft) of snow - enough to cause some roofs to cave in under the pressure.

It's just the latest chapter in 2014 unprecedented range of weather extremes - from persistent storms that battered, and flooded much of the UK at the beginning of the year, before going on to record the hottest October since records began.

And in the US, extremes have ranged from California's record drought, to the early snows now under way in the northeast - and let's not forget the 'polar vortex' that hit much of the US in January, bringing Arctic conditions as far south as Texas and Florida, causing flights to be cancelled in Chicago as aviation fuel froze in the -38.3C (-37F) temperatures.



Scientists now have evidence that these persistent extreme weather patterns are increasing in their frequency, due to the rapid heating up of the Arctic that is changing the behaviour of the jet stream, and in turn, the polar vortex.

And Jennifer Francis of Rutgers University, one of the leading US scientists studying the relationship between Arctic warming and changes in the jet stream, believes that it's thanks to 'global warming' that northern hemisphere weather is becoming more extreme - and it's not about to get any better.

Screenshot from Youtube video further below

The 'vast river of wind' that makes our weather

"The Arctic is generally very cold", she told me, "and the areas farther south are warm, and that difference in temperature between those two areas is really what fuels that vast river of wind moving high over our head that we call the jet stream."

"The jet stream in turn creates most of the weather that we feel all around the northern hemisphere and the middle latitudes, so anything that affects this jet stream is going to affect weather patterns. So as the Arctic warms up much faster than the areas farther south, we're seeing this temperature difference between these two regions get smaller."

The result of that, she explains, is that the atmospheric forces driving the jet stream's circular motion are getting smaller - and that means the winds themselves in the jet stream are getting weaker, and moving more slowly.

"When that happens, the jet stream tends to take a wavier path as it travels around the northern hemisphere and those waves are actually what create the stormy patterns and the nice weather patterns. As those waves get larger because of this weakening of those winds of the jet stream, they tend to move more slowly from west to east."

"That means it feels like the weather patterns are sticking around longer, because those patterns are moving much more slowly and this then makes it more likely to have the kind of extreme events that are related to persistent weather patterns."



Are critical findings influencing policy?

These changes in climate have huge implications. As Dr Francis points out, there are "people who worry about whether there is enough fresh water to supply cities, whether there is enough snowpack on mountains to supply reservoirs, and for agriculture ..."

"Drought and agriculture is a big problem. Storminess in certain areas is another big problem. Yes, it has a huge impact for a whole range of issues that affect the way we live."

It's no wonder then that Dr Francis and her colleagues have attracted the attention of President Obama's chief science advisor, Dr John Holdren.

Dr Holdren has been reporting directly to the President on the real time effects of climate change and is keen to understand what this new research tells us about the future impact of changes to the jet stream.

Asked about this sudden interest in her work from the US Presidency, Francis muses thoughtfully. "Yes, we've had a lot of interest from policy makers", she acknowledges.

"I think we're starting to make a lot of progress now in getting policymakers to understand that this is a big problem they have to face ... I think decision makers and the policymakers at the local level get it much better because they're already seeing effects on their local areas.

"Sea level rise is an obvious one. They're already seeing changes in drought and agricultural problems and dealing with fresh water issues. It is really at the local level that we're having more success."

New research supports the case that Arctic sea ice loss is driving climate changes

So to understand the changes in the jet stream it's important to research how the vast atmospheric river of weather above our heads is connected to other climate mechanisms.

"It appears that over the north Atlantic, and towards Asia, there's a mechanism that appears to be quite robust, and several groups have found this mechanism using completely different analysis techniques", says Francis referring to new research by colleagues at the University of Alaska that has emerged in the last couple of months.

"So what we're finding is that there's an area, north of Scandinavia in the Arctic, where the ice has been disappearing particularly rapidly. When that ice disappears ... there is unfrozen ocean underneath, and that ocean absorbs a lot more energy from the sun through the summertime. So it becomes very warm there."

"Then as the fall comes around, all that heat that's been absorbed all summer long, where the ice has retreated, is put back in the atmosphere and that creates a big bubble of hot air ... over that region where the ice was lost."

And in turn, that goes on to disrupt the circumpolar winds whose behaviour determines much the weather across the northern hemisphere.

The gigantic bubble of warm air "tends to create a northward bulge in the jet stream", and in turn, "that creates a surface high pressure area that circulates in the clockwise direction. That sucks cold air down from the Arctic over northern Eurasia, and that creates a southward dip in the jet stream."



The bulging jet stream disrupts the polar vortex

"So what we're getting is this big northward bulge up over Scandinavia and a southward dip over Asia ... creating, first the tendency for a larger wave in the jet stream, which tends to move more slowly, but also we're seeing this mechanism that creates these colder winters that have been observed over Central Asia."

"Once the jet stream gets into this wavier pattern, it sends wave energy up into the highest levels of the atmosphere, which is called the stratosphere, where we have the polar vortex, which is kind of similar to the jet stream but it's much higher up in the atmosphere and it travels much faster."

"So as that wave energy gets sent up from this larger wave below, up into the stratosphere, it breaks down that polar vortex so that it becomes wavier as well. That wavier polar vortex sends energy back down to the lower atmosphere and it creates an even wavier jet stream in February."

"So we're seeing this connection of mechanisms that starts with Arctic sea ice loss and it makes a wavier jet stream for different reasons all the way through winter."

Will the jet stream continue to cause changes in climate?

By identifying these mechanisms and linking them back directly to loss of the Arctic sea ice, Dr Francis and her colleagues are demonstrating how man-made global warming is creating feedbacks that are changing the climate conditions in the northern hemisphere - and not for the better.

It may be counterintuitive, and it when it first happened it took scientists by surprise - but now it looks like this is one of the most important ways in which 'global warming' is hitting North America. Melting ice in the Arctic Ocean is indirectly pushing frigid Arctic air south across the continent, creating the perfect conditions for massive snowfall.

Which is all very well ... but what's coming next? "We are using these climate models, or computer simulations ... to try and project what we're expecting to see happen in the future, as greenhouse gases continue to increase.

"The early indications are that these large wavy patterns in the jet stream are going to become more frequent in the future, as far as we can tell. It is preliminary research that I haven't published yet but it does look as if they are going to increase."



Nick Breeze is a film maker and writer on climate change and other environmental topics. He has been interviewing a range of experts relating to the field of climate change and science for over four years. These include interviews with Dr James Hansen, Professor Martin Rees, Professor James Lovelock, Dr Rowan Williams, Dr Natalia Shakhova, Dr Michael Mann, Dr Hugh Hunt, among others.

Additional articles can also be read on his blog Envisionation.

Jennifer Francis is a research professor at the Institute of Marine and Coastal Sciences at Rutgers University, where she studies Arctic climate change and the link between Arctic and global climates. She has authored more than 40 peer-reviewed publications on these topics. She was also the co-founder of the Rutgers Climate and Environmental Change Initiative.

Article earlier posted at TheEcologist.org




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