The rise in the occurrence rate and energy of extreme atmospheric events observed in recent decades is a matter of great concern due to the sharp increase in the number of casualties and the amount of economic damage.
For many years, the Intergovernmental Panel on Climate Change (IPCC), functioning as part of the U.N., has investigated the issues of global climate change deeply. Given that the “Atmosphere” section frequently refers to IPCC research results, we consider it necessary to provide brief information about it. (http://www.ipcc.ch).
The Intergovernmental Panel on Climate Change (IPCC) is an intergovernmental scientific body tasked with assessing the risk of climate change caused by human activity. The World Meteorological Organization (WMO) and the United Nations Environment Programme (UNEP) established the Panel in 1988.
The United Nations Framework Convention on Climate Change (UNFCCC) was signed in 1992 as a response to the emergence of increasing scientific evidence of global climate change being determined by anthropogenic alteration of greenhouse gas concentration in the atmosphere. Some global warming consequences, particularly the increased frequency of extreme weather events, melting of mountain glaciers, sea level rise, etc. have quite a negative impact on the natural environment and development of society. The declared long-term goal of the Convention was to stabilize the greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the planet’s climate system. Reducing the anthropogenic emissions of greenhouse gases (the term “mitigation measures” will be used hereinafter in relation to the activity associated with reducing greenhouse gas emissions and increasing their absorption, e.g., planting forests) was named the key type of activity to mitigate climate change. Since emissions are generally caused by burning fossil fuel, the main source of energy in the modern world, such a long-term objective’s formulation by UNFCCC was inevitably bound to have an effect on the development of the global economic system.
The Kyoto Protocol to the UNFCCC was adopted in 1997 in order to deepen the developed countries’ commitments. The Protocol has a limited term of validity (2008-2012) and assigns each country a strictly defined emission level to be observed at end of this period. Thus, emission level in 2012 must be, as compared to 1990, not more than 93% in the U.S., 92% in the European Union, and 100% in Russia. The Kyoto Protocol introduced financial mechanisms such as emissions trading, joint implementation, and clean development to facilitate developed countries’ fulfillment of their commitments.
4.1. HURRICANES, STORMS, TORNADOES:
4.1.1. HURRICANES AND STORMS
According to IPCC data, the number of hurricanes across the world has risen substantially over the last two decades. As follows from NOAA data, U.S. hurricane statistics also points to an increase in their numbers. Below is a graph for Atlantic Basin hurricane statistics from 1944 to 2008.
Fig. 26. Graph for numbers of hurricanes in Atlantic Basin between 1944 and 2008
(According to data http://www.climate.org/topics/extreme-weather/images/north-atlantic-tropical-storms.gif)
Total number of hurricanes graph is marked in blue;Major hurricanes graph is marked in red;
Straight-line trend of total number of hurricanes is marked in green.
It is remarkable that the increase in the number of hurricanes applies to both the most powerful ones and the total number altogether. The straight-line trend shown on the graph in Fig.26 also points to a steadily continuing tendency for the total number of Atlantic Basin hurricanes to increase annually.
Sand Storm in Khartoum, Sudan
Storm in Sevastopol, 11.11.2007
The statistical analysis of the numbers of major Atlantic Basin hurricanes and their total number reveals a certain 4-5 year cyclicity. This cyclicity persists during the entire considered time span.
Fig. 27. North-Atlantic tropical storms frequency variations
by Pew Center on Global Climate Change
Fig.27 contains a diagram by the Pew Center on Global Climate Change, which demonstrates the dynamics of named North Atlantic Basin tropical storms. The graph shows annual numbers smoothed out over a 10-year running average to minimize the noise in year-to-year variation. Since 1996, the tropical storm frequency has exceeded by 40% the old historic maximum of the mid-1950's previously thought to be an extreme value.
This graph shows the climatic changes of recent decades. The straight-line trend points to a persistent tendency for the tropical storm frequency to grow. From the 1990’s to 2007, there have been an extremely high number of North Atlantic tropical storms. (http://www.pewclimate.org/global-warming-basics/facts_and_figures/impacts/storms.cfm)
Examples of major hurricanes in recent years
Hurricane Katrina was the most devastating natural disaster in American history. The complete destruction caused by Hurricane Katrina and the accompanying catastrophic flood has significantly exceeded the consequences of any other large-scale disaster in the U.S.
Hurricane Katrina destroyed much more private property than any other recent hurricane, completely ruining or otherwise making uninhabitable approximately 300,000 homes (http://en.wikipedia.org/wiki/Hurricane_Katrina).
Many times since 1851 hurricane Katrina has struck the United States mainland, the last one being the most powerful and destructive.
Katrina’s hurricane winds and 27 feet high rolling storm wave dealt a fierce blow to homes, farms, and property along the coast and for many miles into the country. This storm wave smashed the dams along the Mississippi River and the edges of Lake Pontchartrain. Its consequences for New Orleans, most of which lies below sea level, were terrible. The flood destroyed New Orleans almost completely. Even beyond New Orleans, the destruction from Hurricane Katrina was enormous. Cities and towns were in ruins or heavily damaged up and down the Gulf coast and for many miles into the country. As Mississippi Governor Haley Barbour stated, “The 80 miles across the Mississippi Gulf Coast is largely destroyed.”
Tornado (synonyms – whirlwind, thrombus, mesohurricane) is a very powerful spinning vortex sized less than 50 km horizontally and less than 10 km vertically with wind speeds of over 33 m/sec.
Tornadoes can be diverse in form, but mostly are shaped like a spinning trunk, pipe, or funnel hanging down from the parent cloud, hence the names: French “tromb” meaning a pipe and Spanish “tornado” meaning “rotating”.
Most tornadoes have wind speeds between 40 mph (64 km/h) and 110 mph (177 km/h), are about 250 feet (75 meters) across and move several miles before dissipating.
The strongest winds can reach speeds of more than 300 mph (480 km/h), be over a mile (1.6 km) across, and travel further than 100 km.
[Wurman, Joshua (2008-08-29). "Doppler On Wheels". Center for Severe Weather Research. http://cswr.org/dow/DOW.htm. Retrieved 2009-12-13.]; [Hallam Nebraska Tornado". National Weather Service. National Oceanic and Atmospheric Administration. 2005-10-02. http://www.crh.noaa.gov/oax/archive/hallam/hallam.php. Retrieved 2009-11-15.]; [Roger Edwards (2006-04-04). "The Online Tornado FAQ". National Weather Service. National Oceanic and Atmospheric Administration. http://www.spc.ncep.noaa.gov/faq/tornado/. Retrieved 2006-09-08.]
A tornado’s rotation direction, like that of cyclones of the Earth’s northern hemisphere, is counterclockwise. The time record for a tornado to exist was set by the Mattoon tornado, which on May 26, 1917 swept 500 km across the U.S. territory for 7 hours and 20 minutes, killing 110 people. The width of the tornado’s loose funnel was 0.4-1 km, with a whip-like funnel visible inside it. Another famous tornado outbreak was the Tri-State Tornado, which on March 18, 1925 crossed the states of Missouri, Illinois, and Indiana, covering the distance of 350 km in 3.5 hours. Its loose funnel’s diameter ranged from 800 m to 1.6 km.
Air rotation inside a northern hemisphere tornado is usually counterclockwise. The reason is related to the directions of mutual movement of air masses around the atmospheric front within which a tornado is formed. Yet there are some cases of inverse rotation.
A phenomenon named cascade – a cloud or column of dust, debris, objects picked from ground, or splashes can occur in the area where the funnel’s base touches the ground or water surface. When a tornado is forming, a cascade goes upwards to meet the funnel descending from the sky and envelop the bottom of the funnel. The term comes from the fact that debris rising to a certain minor height can no longer be held by the airflow and falls to the ground. The funnel can be wrapped by a case without touching the ground. The cascade, case, and mother cloud merging creates an illusion of a funnel wider than it actually is.
A whirlwind over the sea is sometimes called a waterspout, whereas overland it is called a tornado. An atmospheric vortex similar to a tornado but formed in Europe is called a thrombus. Most often, these three terms are considered synonyms.
Tornadoes have been witnessed on all continents except Antarctica. Nevertheless, the vast majority of world tornadoes occur in the U.S. area known as “Tornado Alley”, although they can be found almost anywhere in North America [Sid Perkins (2002-05-11). "Tornado Alley, USA". Science News. pp. 296–298. Archived from the original on 2006-08-25.
http://web.archive.org/web/20060825011156/http://www.sciencenews.org/articles/20020511/bob9.asp. Retrieved 2006-09-20.]
From time to time tornadoes occur in south-central and eastern Asia, the Philippines, the eastern part of central South America, South Africa, north-western and south-eastern Europe, western and south-eastern Australia and New Zealand. ["Tornado: Global occurrence". Encyclopædia Britannica Online. 2009.http://www.britannica.com/eb/article-218357/tornado. Retrieved 2009-12-13].
Tornadoes can be detected before or after they are formed, with the help of pulsed Doppler radar and additional special equipment.
In respect to their scope and energy, tornadoes are classified according to special scales. The Fujita scale rating tornadoes by the damage caused, similar to the seismic scale of earthquake intensity (MSK64), has been replaced in some countries with the updated enhanced Fujita scale. For example, F0 or EF0 class tornados, weak categories, cause damage to trees but no major destruction. F5 or EF5 class tornadoes refer to strong tornadoes, damaging brick-made and prefabricated buildings with their foundations alike and capable of deforming large skyscrapers.
A similar TORRO scale ranges from T0 class for extremely weak tornadoes to T11 class for the most powerful tornadoes [Meaden, Terrance (2004). "Wind Scales: Beaufort, T — Scale, and Fujita's Scale". Tornado and Storm Research Organisation.
http://www.torro.org.uk/TORRO/ECSS_Slide_Show/2004%20SPAIN%20ECSS%20Post-FINAL%20slide%20show.html. Retrieved 2009-09-11.]
Fig. 28. Graph for tornado statistics in Germany since 1800.
Height of columns indicates per decade tornado numbers.
Last column represents tornado numbers for five years (2000-2005)
Fig. 28 provides a graph to demonstrate the dynamics of per-decade tornado numbers in Germany. The last decade only covers a 5-year period (2000-2005). Meanwhile, as is seen in the graph, there were 2.5 times more tornadoes in Germany between 2000 and 2005 (for 5 years) than over the preceding ten years.
A similar situation with the increased tornado rate can be observed for the territory of the United States as well. Fig. 29 shows graphs for tornado numbers from 1950 to 2007 for different tornado classes. The graphs also reflect a steady increase in the number of tornadoes of all classes in the U.S. over the last two decades.
Fig. 29. Graphs for U.S. all-class tornado activity
between 1950 and 2007
Fig. 30. US tornado numbers from 1950 to 2007
Fig. 30 shows a graph for the annual changes in the number of U.S. tornadoes together with a straight-line trend that demonstrates the general nature of the annual increase in tornado numbers from 1950 to 2007.
Fig.31. Graph for Earth’s global temperature change
Fig. 31 demonstrates the global change of the Earth’s temperature from 1900 to 2005, according to data by IPCC.
4.2. FOREST FIRE STATISTICS
Forest fires are in the list of our planet’s global natural disasters that cause enormous damage to the environment and ecology as well as great economic damage every year. They often kill people and large numbers of animals. In addition to destruction of huge areas of forest, irreversible damage is done to the flora and fauna. Statistics for forest fires all over the world shows that their number and area are expanding from year to year.
According to the U.S. National Interagency Fire Center, forest fires spread over the area of 9.7 million acres in 2006 and 9.3 million acres in 2007. In each of these years, the burned area rate is the worst for the last 50 years. The number and extent of US forest fires are substantially increasing from year to year (http://www.nifc.gov/fire_info/fire_stats.htm).
Fig. 32. Annual rates of total area affected by U.S. fires between 1960 and 2007,
with trend indicating tendency for significant increase in values.
(According to U.S. National Interagency Fire Center, http://www.nifc.gov/fire_info/fire_stats.htm)
Fig.33. Annual rates of average fire-affected area in U.S.
between 1960 and 2007
(According to U.S. National Interagency Fire Center,
Fig. 32 and Fig. 33 contain graphs showing the annual rates of the total and average area affected by forest fires in the United States from 1960 to 2007. The graphs clearly demonstrate that since 1995, there has been a tendency for a sharp increase in the U.S. fire rates, which were virtually invariable for the prior 35 years.
Fig. 34. Forest fire statistics in Latvia, 1980-1999
(According to http://www.fao.org/docrep/006/AD653E/ad653e75.htm)
Dynamics of forest fires in Latvia from 1980 to 1999 demonstrate a steady growth as well (Fig. 34). In 1992, Latvia witnessed a surge in the number of forest fires.
Fig. 35. Forest fire dynamics in Kazakhstan
Diagram reflects annual rates of forest fire affected areas;
Curve reflecting dynamics of annual numbers of forest fires (N) is marked in blue;
Curve reflecting fire affected areas is marked in green.
A very interesting regularity is found in relation to the dynamics of forest fires in Kazakhstan. In addition to the trend demonstrating a general tendency for the rates to grow, two distinct cycles of sharply increased forest fire statistics in 1973-1975 and 1996-1999 can be observed in the diagram for the annual numbers of forest fires and areas affected by them (Fig. 35). The last cycle with its peak in 1997 is the biggest in the last 50 years.
Fig. 36. Dynamics of annual rates of forest fires in mainland Portugal
According to statistical data by DGRF
1 – fire incidents; 2 – fires covering areas of ≥ 1 ha;
3 - fires covering areas of <1 ha
Fig. 37. Dynamics of annual rates of forest fire affected areas
in mainland Portugal
According to statistical data by DGRF1 - burned woodland areas;
2 – burned undergrowth areas
Fig.36 and Fig.37 contain graphs showing the dynamics of forest fire statistics in mainland Portugal for 40 years, from 1968 to 2007. Along with the fact that the graphs indicate a steady annual growth of statistical indicators, we can see that the number of forest fires in Portugal has risen sharply since 1995 and this that trend continued until 2005, followed by some decline in 2006-2007. Some increase with a surge in 2003 and 2005 can also be observed in the dynamics of annual rates of areas affected by forest fires.
Fig. 38. Graph for dynamics of areas affected by forest fires
in Eastern and Western Europe and the CIS
The dynamics of areas affected by forest fires in Eastern and Western Europe and the CIS between 1970 and 2000 demonstrates steady growth for the CIS, with a surge in 1998.