The Tornado Connection to Climate Change

By  Paul Beckwith, B.Eng, M.Sc. (Physics), Ph.D. student (Climatology) and Part-time Professor, University of Ottawa

"In 2012, 93 percent of natural catastrophes were weather-related disasters. The United States was seriously affected: it accounted for 69% of overall losses and 92% of insured losses due to natural catastrophes worldwide." ~ World Watch Institute

"America has some of the wildest weather on the planet, and it turns out those extremes – which run from heat waves and tornadoes to floods, hurricanes and droughts – carry a heavy price tag." ~ theguardian

3D look at the Moore Oklahoma thunderstorm and tornado, up to 50,000 ft. Image by Tony Petrarca
from Tony's Pinpoint Weather Blog showing the funnel touching the ground just outside of Moore. 

The mega-storm that generated the massive cyclonic system that passed over the central U.S (from May 18th through May 20th) spawned many storm systems and severe tornadoes. In Oklahoma, it took less than 1 hour for a thunderstorm system to develop into a full-blown 3 km diameter tornado of the highest size/strength (EF5). As you know, this tornado caused total devastation along a swath greater than 30 km long and about 3 km wide in the southern part of the city. Two schools and a hospital were destroyed resulting in heavy loss of life.

The actual tornado tracked through the most built up part of the city and had a length of 6.22 km (Image 2). As bad as this was, if the tornado had tracked further north by about 10 km, the path length through the built-up part of the city would have been about 28 km and likely would have resulted in FOUR TIMES MORE DAMAGE.

The high altitude jet stream guided this storm directly over Oklahoma City and was a key ingredient responsible for the extremely rapid development of the tornado witnessed. Unfortunately, the location, strength, waviness, and behavior of the jet stream is changing as a result of rapid climate change. You can get use to more “Climate Bomb” extreme weather events – there is nothing to be surprised about here.

Greenhouse gas emissions from humans have warmed the planet since about 1850; the warming rate has stepped up a notch over the past several decades, and even more so now with ‘feedbacks’ kicking in big time.

There is less snow cover on the land over northern Canada, northern Eurasia and Siberia, and there is less sea ice over the Arctic Ocean. The snow and ice reflects greater than 80% of the incoming light from the sun back into space keeping these areas colder. With less snow the dark land is uncovered and with less sea ice the dark ocean is uncovered. These both reflect much less light; only about 20% and 10% respectively. The rest is absorbed and heats the ground and sea. The melting ground is releasing methane; the warming sea heats the sea floor and that warming releases more methane. Thus, parts of the high Arctic are warming at 5 to 6 times the average global rate. The equator temperature does not change as much (even seasonally the change is only about 3°C over the year). Thus, the temperature gradient between the equator and Arctic is greatly reduced.

By basic physics and meteorology, this reduced equator-pole temperature difference slows the west to east wind component. Fast jet streams circle the earth from west to east; as they slow they become much wavier and travel much more northward and southward. Regions north of the wavy jets are cold and dry (air source is cold Arctic) while regions south of the wavy jets are hot and moist (air source is equatorial marine regions). The jet is thus an intersection of these two different types of air masses (with cold fronts and warm fronts, respectively). The large local temperature gradients give rise to large pressure gradients resulting in extreme (and very unstable) weather regions.

May 20, 2013 Moore, Oklahoma tornado

Since the wave troughs carry cold air very far south and the wave crests carry warm moist air far north, the frontal temperature gradients are larger under climate change then they were before and thus the storm magnitudes are now larger. That’s why I wrote earlier that we shouldn’t be surprised.

Global warming also brings greater ocean evaporation and warmer air can carry more water vapor – in fact, in the last 3 decades or so there has been a 4% increase in atmospheric humidity. When this water vapor condenses to forms clouds, energy is released. Greater energy in the atmosphere thus fuels more violent storms, and Climate Bombs are born.

The Oklahoma tornado is just another example of the global ‘weirding‘ that we are seeing. Our reference frame is the “old climate”, in which the equator-polar temperature gradients are smaller, but the local frontal temperature gradients are larger. In our “new climate” (in which there is much less sea ice in the Arctic) this type of tornado will be much more probable — at least while we abruptly transition from the “old” to the “new” and unfamiliar climate.

Our future is a world with much warmer global temperatures. Paleoclimate records show temperature rises of 6 to 10°C within two decades have occurred many times in the past over Greenland; in one case the rise was 16°C. I see no reason why this will not occur again.

Put your seat belt on . . . oil profits can’t save you from Climate 2.0.

[earlier published at Paul's blog at SierraClubCanada and BoomerWarrior]

Related posts

- Killer El Reno Tornado Was Widest Ever Recorded: NWS

http://www.climatecentral.org/blogs/killer-el-reno-tornado-was-widest-ever-recorded-nws

- Climate change causing US wildfire season to last longer, Congress told

http://www.guardian.co.uk/world/2013/jun/04/climate-change-america-wildfire-season

Update on Arctic Snow and Ice

Above image, adapted from the National Snow and Ice Data Center (NSIDC), shows that Arctic sea ice extent has roughly followed the same path it did in 2012 when it reached a historic record low. Highlighted on above image is the highest extent the sea ice reached in 2013, i.e. 15,113 million square km on May 14, 2013.

Is the permafrost's integrity breaking down?

The chart below shows very high methane levels over Antarctica in April and May 2013. High levels of methane over Antarctica were recorded before in 2013, as described in an earlier post at the methane-hydrates blog.

Meanwhile, a methane reading of 2475 ppb was recorded on April 26, 2013, appearing to originate from the Himalayan Plateau, as illustrated by the image below.

Recurring high readings could indicate that methane is bubbling up through the permafrost, both in Antarctica and on the Himalayan Plateau.

Loss of the integrity of the permafrost is particularly threatening in the Arctic, where the sea ice looks set to disappear within years, resulting in huge albedo changes in summer. Decrease of surface reflectivity results in increases in absorption of energy from sunlight and decreases in shortwave radiation in the atmosphere. The latter results in lower photo-dissociation rates of tropospheric gases. Photo-dissociation of the ozone molecule is the major process that leads to the production of OH (hydroxyl radical), the main oxidizing (i.e., cleansing) gas species in the troposphere. A 2009 NASA study projects this to lead to a decrease in OH concentrations and a weakening of the oxidizing capacity of the Arctic troposphere, further increasing the vulnerability of the Arctic to warming in case of additional methane releases.

Levels of greenhouse gases such as carbon dioxide and methane are already very high in the Arctic atmosphere, while large quantities of black carbon get deposited on snow and ice, further contributing to the albedo changes. This threatens to result in rapid summer warming of many parts of the Arctic Ocean with very shallow waters. Additionally, rivers can bring increasingly warm water into those shallow seas in summer, adding to the threat that heat will penetrate the seabed that contains huge quantities of methane.



Above image, earlier included in an animation at the Arctic-news blog, shows methane concentrations on January 23, 2013, when a reading of 2241 ppb was recorded in the Arctic.

Analysis of sediment cores collected in 2009 from under ice-covered Lake El'gygytgyn in the northeast Russian Arctic suggest that, last time the level of carbon dioxide in the atmosphere was about as high as it is today (roughly 3.5 to 2 million years ago), regional precipitation was three times higher and summer temperatures were about 15 to 16 degrees Celsius (59 to 61 degrees Fahrenheit), or about 8 degrees Celsius (14.4 degrees Fahrenheit) warmer than today.

As temperatures rose back in history, it is likely that a lot of methane will have vented from hydrates in the Arctic, yet without causing runaway warming. Why not? The rise in temperature then is likely to have taken place slowly over many years. While on occasion this may have caused large abrupt releases of methane, the additional methane from such releases could each time be broken down within decades, also because global methane levels in the atmosphere were much lower than today.

In conclusion, the situation today is much more threatening, particularly in the East Siberian Arctic Shelf (ESAS), as further described in the earlier post methane hydrates.

Above post is an extract of the full post at the methane-hydrates blog. 

1250 - New group calls for action on methane

A new group, named 1250, calls for governments around the world to take action on methane.

Just like 350 parts per million has become a popular target for carbon dioxide, the group similarly advocates a target for methane, aiming for a reduction of methane to 1250 parts per billion (ppb).

On several occasions in April, 2013, the hourly average carbon dioxide concentration in the atmosphere of Mouna Loa, Hawaii, surpassed 400 parts per million (ppm). On May 9, 2013, the daily mean concentration of carbon dioxide in the atmosphere of Mauna Loa also surpassed 400 ppm. The National Oceanic and Atmospheric Administration (NOAA) comments that before the Industrial Revolution in the 19th century, global average carbon dioxide was about 280 ppm. During the last 800,000 years, carbon dioxide fluctuated between about 180 ppm during ice ages and 280 ppm during interglacial warm periods. Today’s rate of increase is more than 100 times faster than the increase that occurred when the last ice age ended.

On May 9, 2013, at another place on Earth, another significant event took place. Methane levels above Antarctica reached a peak of 2249 ppb, highlighting the need for action on methane.

The group 1250 advocates a similar target for methane, i.e. a reduction of methane to 1250 parts per billion.

“Methane is far more potent than carbon dioxide as a greenhouse gas, making it important to reduce levels of methane in the atmosphere,” explains founder Nathan Currier; “1250 is not just an advocacy group for methane cuts, however. Rather, it is a group focusing on near-term climate as a whole, and on practical pathways to constructing a ‘climate bridge’ towards a stable and sustainable future.”

The launch of the group is accompanied by the release of the chart below showing the very high methane levels that have been recorded over Antarctica recently. The chart was prepared by Sam Carana, who also is a founding member of 1250.

These very high methane emissions occur on the heights of East Antarctica. Antarctica is covered in a thick layer of ice. It appears that these very high emissions are caused by methane from hydrates that is escaping in the form of free gas bubbling up through the ice sheet.

The danger is that such emissions will escalate, not only over Antarctica, but also on the Qinghai-Tibet Plateau and in the Arctic. For more on this, see the methane-hydrates blog.

The group 1250 was set up specifically to address to need for a comprehensive approach to the challenges posed by climate change. The group now invites other groups to a dialogue regarding the details.

The group has a website at http://1250now.org/ and encourages people to join its mailing list and sign its petition.