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.
Extreme weather is upon us. Global warming is increasing the intensity, occurrence, size, duration and impact of many catastrophic events, including wildfires, droughts, heat waves, cold snaps, storms, lightning, flooding and seismic events such as earthquakes and associated tsunamis.
Ever larger numbers of people are getting hit directly by such events, as well as indirectly due to lack of fresh water, food, shelter, medicine, health care and emergency services.
Many lives were lost and many further lives are at stake. In a September 11, 2017, statement, AccuWeather predicts the joint economic costs of Hurricane Harvey and Hurricane Irma to be $290 billion, or 1.5% of the U.S. GDP.
The following three images show Hurricane Irma (left) and Hurricane Jose (right), and are forecasts for September 10, 2017. The image directly below shows that waves are forecast to be as high as 48 ft (or 14.63 m).
Waves for September 10, 2017, 15:00 UTC (at green circle, 26°N, 80°W) are forecast as high as 48 ft or 14.63 m
The image below shows that winds are forecasts to be as fast as 163 mph (or 263 km/h).
Winds for Sept. 10, 2017, 12:00 UTC (green circle, 25.5°N, 80.5°W, 850 hPa) forecast as fast as 163 mph or 263 km/h
The image below shows that as much as 6.59 in (or 167.4 mm) of rain is forecast.
As much as 6.59 in (or 167.4 mm) of rain is forecast for Sept. 10, 2017, 6:00 UTC (3-hour accumulation, green circle)
Forecasts were posted widely, such as the image below that was posted at facebook.
Earlier, Hurricane Harvey hit Houston. Again, warnings were posted widely, such as the forecast below, posted at facebook.
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There is no doubt that people's emissions are causing global warming and that this is causing more extreme weather to occur across the world.
Extreme weather is amplified by changes to the Jet Streams. As the Arctic is warming more rapidly than the rest of the world, the temperature difference between the Arctic and the Equator is narrowing, which is slowing down the speed at which the Jet Streams circumnavigate the globe.
The Coriolis Effect makes Jet Streams circumnavigate the globe horizontally, and this used to keep cold air inside the Arctic and warmer air outside of the Arctic.
As the Jet Streams circumnavigate the globe at lower speeds, they increasingly move more vertically, allowing cold air from the Arctic to move down south more easily, and warm air to move up north more easily. This can make it easier for cyclones to move land-inward, where they previously would have kept following a path over the sea. This can also make it easier for weather conditions to stay the same for many days in an area, allowing huge amounts of rain water to accumulate in such an area.
This is illustrated by the image on the right, showing Jet Streams crossing the Equator at speeds as fast as 82 km/h or 51 mph (at the location marked by the green circle, at 250 mb) on August 27, 2017, 21:00 UTC. The image also shows Jet Streams crossing the Arctic at multiple locations.
Furthermore, numerous cyclones are visible on the image. As Earth retains more energy, winds and currents are getting stronger, waves are getting higher, etc., while higher temperatures are also causing winds to carry more moisture. This is especially the case for cyclones that are also stronger due to high sea surface temperatures.
The image below shows Hurricanes Jose, Irma and Katia lining up over the Atlantic Ocean on September 7, 2017.
The image below shows the hurricanes lining up over the Atlantic Ocean on September 8, 2017.
The image below shows Hurricane Jose off the coast of North America and Hurricane Maria underneath, with winds as fast as 149 mph or 241 km/h (at 850 hPa) and as much as 7.92 inch or 201.1 mm of rain (3-hour precipitation accumulation) at the location marked by the green circle.
There can be many interactions between such events. Seismic events such as earthquakes, landslides and associated tsunamis, can be triggered by human activities in several ways.
Seismic events triggered by human activities
• Earthquakes can be triggered by fracking and by pools associated with fracking.
• Warming caused by people makes snow and ice melt, removing weight off the land and dumping it into the sea. This change in weight can trigger earthquakes.
• The Earth's crust can be flexed by storms. Large cyclones first suck up water, making sea level retreat and lifting up the crust. Then, a surge follows, while huge amounts of rainwater can add further weight, pushing the crust down again. This change can be felt over longer distances, triggering earthquakes across continents.
• Wild weather swings can be the result of changes in the jet streams caused by global warming. Huge sudden swings in temperature and in air pressure can make soils and ice go abruptly from expansion to compression and back again, which can cause cracks and landslides, and associated shockwaves, which can in turn trigger larger seismic events and open up methane craters with can come with large releases of methane.
After Sandy hit New York, in 2012, earthquakes hit the coast off Vancouver and links between the two events were discussed in this post.
Hurricane Harvey caused massive flooding in several States. The weight of the torrential rains brought by Hurricane Harvey caused Houston to sink by 2 centimeters. Water weighs about a ton per cubic meter and the flooding was so widespread that it "flexed Earth's crust", NASA scientist Chris Milliner said.
An earthquake with a magnitude of 8.1 on the Richter scale hit at 69.7 km depth, off the coast of Mexico, 87km SW of Pijijiapan, on September 8, 2017 at 04:49:21 UTC, at 15.068°N 93.715°W.
Numerous aftershocks are visible on the map below (screenshot taken September 13, 2017).
Rising temperatures are increasing the amount of water vapor in the atmosphere at a rate of 7% more water vapor for every 1°C warming. This is further speeding up warming, since water vapor is a potent greenhouse gas. Over the coming years, a huge amount of additional water vapor threatens to enter the atmosphere, due to the warming caused by albedo changes in the Arctic, methane releases from the seafloor, etc., as described at this page.
The situation is dire and calls for comprehensive and effective action, as described at the Climate Plan.
Hurricane Damage Mitigation
A 2014 study by scientists led by Mark Jacobson calculates that large turbine arrays (300+ GW installed capacity) could diminish peak near-surface hurricane wind speeds by 25–41 m/s−1 (56–92 mph) and storm surge by 6–79% AND provide year-round clean and renewable electricity.
How many electric cars will be ready to move into Miami to provide emergency support in the wake of Hurricane Irma?
Storms can cause power outages, electricity poles can get damaged. Electricity poles can also be a traffic hazard (i.e. collisions can occur even if the pole hasn't fallen down, especially when streetlights fail). When damaged, power lines hanging off poles constitute electrical shock hazards and they can cause fires to ignite and wildfires to start.
Storms can also cause damage to backup generators and to fuel storage tanks, making it hard for emergency services to give the necessary support. Electric cars can supply electricity where needed, e.g. to power necessary air conditioning, autoclave and emergency equipment, such as in hospitals. After a tsunami hit Japan in 2011, electric cars moved in to provide electricity from their batteries, as described in many articles such as this one.
Wind turbines and solar panels are pretty robust. Hurricane Harvey hit the Papalote Creek Wind Farm near Corpus Christi, Texas. The wind farm had little or no damage, there was just a short delay in restarting, mostly due to damage to power lines. The Tesla roof that doubles as solar panels is much stronger than standard roofs. Have a look at this video.
Clean and renewable energy can provide more stable, robust and safe electricity in many ways. Centralized power plants are vulnerable, in that all eggs are in one basket, while there can be long supply and delivery lines. Many of the benefits of clean and renewable energy are mentioned on above image.
Furthermore, there are ways to lower sea surface temperatures. The image on the right shows the very high sea surface temperature anomalies on August 28, 2017.
Note the colder area (blue) in the Gulf of Mexico. Hurricane Harvey cooled the sea surface as water evaporated and warm moisture was added to the atmosphere. The cyclonic force also mixed colder water below the surface with warmer water at the surface, resulting in colder water at the surface. The combination image below shows the difference between August 20, 2017, and August 30, 2017.
Besides cooling the sea surface, there's also the upwelling of nutrients that can help combat ocean stratification. Warm water holds less oxygen than cold water. As the water warms, it also tends to form a layer at the surface that does not mix well with cooler, nutrient-rich water below, depriving phytoplankton of some of the nutrients needed in order for phytoplankton to grow (and take up carbon).
Some of these methods are also discussed at this 2011 page, which also mentions that more research is needed into the impact of such methods. Of course, possible application should go hand in hand with dramatic reductions in emissions including a rapid shift to 100% clean and renewable energy.
Similarly, the necessary shift to clean and renewable energy in itself will not be enough to avoid catastrophic warming, and it should go hand in hand with further lines of action to remove pollution and to cool the Arctic Ocean, as described at the Climate Plan.
How much could temperatures rise by 2026? The above image shows how a rise of 10°C (18°F) could occur by the year 2026, based on temperature anomalies from 1750 for February and on progressive growth of warming elements. The image below shows the same rise in another way.
Such a rise could take place even more rapidly, as discussed in the earlier post 10°C or 18°F warmer by 2021? For more on calculating the temperature rise from 1750 to 2016, see this page and this post.
Crucial will be the decline of snow & sea ice and associated feedbacks. Ominously, global sea ice is at a record low at the moment, as illustrated by the graph below by Wipneus.
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Arctic sea ice extent on August 15, 2017, was the 2nd lowest on record for the time of year (behind only 2012), as illustrated by the image on the right.
While extent was lower on August 15, 2012, Arctic sea ice is very thin at the moment, as the Arctic Ocean has become warmer, and sea ice could disappear altogether in one month time, as discussed in earlier posts such as this one.
And ominously, July 2017 was the hottest July on record, as illustrated by the image below.
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The July temperature anomaly was particularly high on land on the Southern Hemisphere (1.53°C or 2.75°F, compared to 1901-2000), as illustrated by the image on the right, showing a linear trend over the period 2012-2017.
Above image shows that July 2017 was 2.25°C (4.05°F) warmer than the annual global mean 1980-2015 (seasonal cycle). Only in August 2016 was it warmer (2.29°C), but then again, August 2017 looks set to be warmer than that yet.
The fall in thickness of the sea ice indicates that the buffer has gone that until now has consumed heat entering the Arctic Ocean during the melting season. In the absence of this buffer, where can all this extra heat go? Sea ice will start sealing off much of the surface of the Arctic Ocean by the end of September 2017, making it hard for more heat to escape from the Arctic Ocean by entering the atmosphere.
The danger is that much of the extra heat will instead reach sediments at the seafloor of the Arctic Ocean that contain huge amounts of methane in currently still frozen hydrates.
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Higher temperatures could destabilize methane hydrates, resulting in huge methane eruptions.
A polynomial trend, based on NOAA July 1983 to January 2017 global monthly mean methane data, points at twice as much methane by 2034, as the image on the right shows. Stronger methane releases from the seafloor could make such a doubling occur even earlier. Over the next decade, methane will cause more warming than CO₂─ twice as much methane will cause more than twice as much warming.
Methane reached peaks as high as 2881 ppb at 479 mb on August 18, 2017, as the combination image below shows (left panel, top left corner).
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The image doesn't specify the origin of the peak, but when levels are that much above the mean, the likely cause is either wildfires or clathrate destabilization. As the image in the right panel shows, methane levels at 280 mb were also very high over the Arctic Ocean north of Canada in the morning that day, which is unusual at such an altitude.
The image below shows that mean global methane reached a level of 1881 ppb at 280 mb (MetOp-1, am) on August 15, 2017.
The situation is dire and calls for comprehensive and effective action, as described at the Climate Plan.
Sun at 8:00 am, captured by Jim Reeve on August 7, 2017 near Sechelt AirPort, B.C., Canada
Arctic sea ice is under attack from all sides. At this time of year, the sun doesn't set at the higher latitudes.
As the image below shows, it was as hot as 94°F or 34.5°C in North Canada on August 13, 2017 (at the green circle, at 1000 hPa, at 00:00 UTC). Temperatures at surface level were as high as 33.1°C or 91.5°F at that location, where wind was coming from the south and blowing toward the north at a speed of 28 km/h or 17 mph at that time.
Above image shows cyclonic winds over the Arctic Ocean pulling warm air from North Canada over the Arctic Ocean, while pushing cold air out. Winds and rain have been battering the sea ice for some time now, as discussed in an earlier post.
Fires are becoming more devastating, as discussed in an earlier post. The August 2, 2017, satellite image below shows smoke from fires in British Columbia blanketing Vancouver and Seattle. Carbon dioxide (CO₂) levels were as high as 527 ppm, carbon monoxide (CO) levels as high as 12.59 ppm and sulfur dioxide (SO₂) levels as high as 490.77 µg/m³, as these images show.
The combination image below shows forecasts for August 8, 2017, 13:30 UTC. CO levels were forecast to be as high as 29.05 ppm, CO₂ levels as high as 625 ppm and SO₂ levels as high as 1089.65 µg/m³ (each time at the green circle). Also note the emissions from forest fires in Siberia.
Actual levels were even higher at that spot on August 11, 2017, when CO was as high as 30.97 ppm, CO₂ was as high as 633 ppm and SO₂ was as high as 1150.19 µg/m³, as illustrated by the image below.
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The image below, by Harold Hensel, shows smoke over British Columbia, Washington, and Montana on August 9, 2017.
Winds can carry smoke from forest fires over long distances, all the way to the Arctic sea ice, where the soot can settle and darken the ice, thus speeding up its decline. The image below, also by Harold Hensel, shows smoke from fires in Russia entering the Arctic Ocean near the Laptev Sea on August 9, 2017.
The image below shows the situation on August 14, 2017.
Canadian wildfires caused PM10 to reach levels as high as 11,599 μg/m³ on August 16, 2017, at the location marked by the green circle. The image below shows PM10 getting blown over the Arctic Ocean.
The thickest sea ice in the Arctic Ocean is located close to the north of Greenland and the Canadian Archipelago. This ice is now breaking up, due to high temperatures and strong cyclonic winds that cause warm rain, high waves and strong sea currents.
Watch the thickest sea ice break up on the animation below. This is a 17 MB file, so it may take some time to fully load. Click here if you do not see the file appear below.
