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For many years climate assessments have predicted that global warming (IPCC 2001) will increase extreme weather events. Now we know they are increasing (IPCC special report 2012)
The heat waves droughts and fires are increasing dramatically but so are extreme precipitation events. All of these are damaging to crops and to agricultural land increasing soil erosion.
This short video from Climate Central explains the basics of extreme weather.
Extreme weather events is a 'reason for concern' category under IPCC assessments.
This extreme weather category is the main cause of damage to human habitations, human health and crops making it priority one for global climate change. For labor intensive agriculture extreme weather is doubly damaging to food production. However, until recently science could not confirm that global warming was already driving increases.
As of 2012-2013 several papers have determined that extreme weather is now increasing and being driven by global warming. A 2011 article series by Scientific American (Storm Warnings: Extreme Weather Is a Product of Climate Change) reported on scientists who were making the link.
A 2012 PNAS paper by James Hansen showed that global warming is driving an increase in extreme heat-an "important change is the emergence of a category of summertime extremely hot outliers, more than three standard deviations warmer than the climatology of the 1951–1980 base period. This hot extreme, which covered much less than 1% of Earth’s surface during the base period, now typically covers about 10% of the land area. It follows that we can state, with a high degree of confidence, that extreme anomalies such as those in Texas and Oklahoma in 2011 and Moscow in 2010 were a consequence of global warming."
A decade of weather extremes by Dim Coumou & Stefan Rahmstorf was published in Nature March 2012
"Here, we review the evidence and argue that for some types of extreme — notably heatwaves, but also precipitation extremes — there is now strong evidence linking specific events or an increase in their numbers to the human influence on climate. For other types of extreme, such as storms, the available evidence is less conclusive, but based on observed trends and basic physical concepts it is nevertheless plausible to expect an increase."
The rapid increase is Northern hemisphere extreme weather threatens global catastrophe because all the world's best food producing regions are in the Northern hemisphere. The prolonged drought affecting the US great grain belt region is of grave concern. This northern hemisphere extreme weather is being driven by the rapid loss of Arctic albedo cooling impacting of top of NH warming. Scientists have called the Arctic summer sea ice 'the air conditioner of the entire Northern hemisphere'. This air conditioning affect is from Arctic albedo cooling as a whole. The Far North snow provides about half the NH albedo cooling influence and is most important with respect to increasing NH drought. The loss of Arctic sea ice is altering the jet stream and this increasing all extreme weather events and also has a blocking effect on the weather prolonging the extremes (research by Jennifer Francis).
Global warming increases heat waves, drought, wildfires, storms and floods
It was always predictable by the basic science that constant atmospheric GHG pollution, with increasing GHGs in the atmosphere, would lead to increased extreme weather. Global warming will increase extreme heat leading to increased drought, which together will increase the risk of wildfires. Global warming increases atmospheric water vapor because warm air holds more water vapor, and water vapor feedback increases warming. The increased GHG heat in the lower atmosphere increases lower atmosphere energy energizing of the hydrological cycle, leading to stronger winds, more heavy rains and flooding.
The strength of cyclonic storms, such as hurricanes, is increased by increased lower atmosphere energy and surface ocean warming.
As global warming increases, climate extremes increase along with the average temperature and climate. The most obvious is heat waves.
Global warming has so far significantly increased extreme heat events.
Computer models studies confirm that as global warming rises so will heat waves. By 2040 the areas affected will have increased several fold, and we are committed to this by climate system inertia.
Climatic warming of about 0.5 ° C in the global mean since the 1970s has strongly increased the occurrence-probability of heat extremes on monthly to seasonal time scales. For the near-term (i.e., by 2040), the models predict a robust, several-fold increase in the frequency of such heat extremes, irrespective of the emission scenario. Unmitigated climate change causes most (>50%) continental regions to move to a new climatic regime with the coldest summer months by the end of the century substantially hotter than the hottest experienced today.
Climate science treats 'Extreme weather events' as one global climate change impact category. The IPCC lists it as one of five Reasons for Concern (see side bar).
For many years scientists have predicted that global warming would increase weather extremes.
Extreme weather is the most damaging climate change impact on both human population health (IPCC 2001) and agriculture. Therefore, the incidence and strength of extreme weather is the best indicator of global climate change damage.
It is now definite that global warming is driving the recorded increase in extreme weather, notably and especially in the Northern hemisphere.
Tropical cyclones, the most severe of which are called hurricanes in the Atlantic and typhoons or cyclones elsewhere, are the most extreme weather events.
The issue of increasing hurricane activity has been hard to pin down, but now research indicates there will more and worse hurricane Katrinas. New research from Lawrence Livermore US suggests that hurricanes will become more frequent and more intense (Guardian 26 July 2013). Research from China 2013 also finds hurricanes that form in the Atlantic Ocean are expected to gain considerable strength as the global temperature continues to rise. New research (Jan 2013) suggests that tropical cyclones in other ocean basins will also become more frequent and more intense. We are already experiencing all the others: extreme damaging heat waves, droughts, storms, rains and floods- significantly affecting the normally temperate Northern Hemisphere regions.
The cause of the NH extremes is GHG global warming and the related the rapid loss of Far North snow and Arctic sea ice albedo cooling. The NH climate is being made chaotic by global warming and its Arctic amplification.
A 2013 paper from the Potsdam Institute for Climate Impact Research on amplification of planetary waves and recent Northern Hemisphere weather extremes complements the now well known research by Jennifer Francis on loss of Arctic sea ice induced jet stream alterations and research on increased NH heat extremes. The developing situation in the Potsdam paper is that the observed increases in number of summer months with high amplitude NH wave numbers is the result of ongoing global warming,and a mechanism for how global warming contributes to future extreme summer events. This complements earlier results by Stott et al. (2004) and Rahmstorf and Coumou (2011). Atmospheric conditions already have changed to the extent that the considered wave amplification will occur frequently. The most recent example would be the destructive heat waves in the United States and southern Europe, as well as the catastrophic floods in China and Japan in June–July 2012. The NH is in big climate change trouble, in other words.
Examples of US extreme weather include both the 2012 heat & drought, wildfires, and the flooding in Colorado in the summer of 2013.
As this article by Climate Central's Andrew Freedman makes clear, through mid-summer, 2013 was one of the drier years on record, an important factor in the huge, record-setting wildfires seen in that state over the summer. Then, one extreme suddenly shifted into the other, dropping half of Colorado's average annual rainfall in just a few days. Mr. Freedman's article does a good job of explaining the unusual weather conditions that caused the flood, as well as the relationship between this specific weather event and climate change. A Climate Progress article by Katie Valentine brings home the severity of the Colorado floods very well.
As global temperatures steadily increase, so too does the risk of wildfires. Wildfire risks around the world are likely to change dramatically during the latter half of this century, with some types of terrain projected to see dramatic increases in likelihood and in the expanse of fire-prone areas during the next 30 years, according to a new study. Fire regimes form an essential ecological role in natural ecosystems, and consequently, any shift in fire ecology can potentially alter ecosystem dynamics with possible negative impacts on species diversity, with endangered wildlife being most vulnerable.
Jeff Masters' summary of the extreme weather events across the globe in 2010 is available from Wunderground. He does a good job of putting that strange year in the context of climate change as well.
The United States was not alone in being flooded. The flooding of Alberta, Canada in June 2013 was the costliest in Canadian history, and another example of weather patterns becoming increasingly unpredictable. An account of the flooding can be found here.
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For the near-term (i.e., by 2040), the models predict a robust, several-fold increase in the frequency of heat extremes, irrespective of the emission scenario. Historic and future increase in the global land area affected by monthly heat extremes. Coumou Envtal Research Letters Aug 2013
"The last decade has
produced record-breaking heat waves in many parts of the world. At the same
time, it was globally the warmest since sufficient measurements started in the
19th century. Here we show that, worldwide, the number of local record-breaking
monthly temperature extremes is now on average five times larger than expected
in a climate with no long-term warming. This implies that on average there is an
80 % chance that a new monthly heat record is due to climatic change."
Extremely Bad Weather Science News J Raloff 2012
Increase in extreme weather in a warming world Stefan Rahmstorf and
Global warming has increased monthly heat records by a factor of five
Potsdam Climate Impacts Institute 2013
The US is the biggest world blocker of any international agreement to reverse GHG emissions, but it is highly vulnerable to global climate change increased weather extremes. It will be hit by more increasing heat waves droughts and floods (report June 2013)- all bad for its great food productivity.
We are well aware of US heat and drought damage to food production since 2012, but global warming also increases floods and that is also damaging to food production. Global warming can cause increased drought and increased floods in the same region. NOAA reports US billion dollar weather disasters. In 2012, there were 11 weather and climate disaster events with losses exceeding $1 billion each across the United States. This makes 2012 the 2nd costliest year on record. 2005 was the most costly year since 1980 with $160 billion (in 2005 dollars) and 2005 was a record global temperature year.
Global warming IS increasing heat waves, forest fires, drought, storms, & floods.
The IPCC AR5 chart above records that all extreme weather events have been increasing since 1950 (i.e. likely), with climate change contributing to the increase. We can expect the increases will continue to 2035 and on to 2100. The terrible news about this is that we are locked into increasing climate change to 2030, due to climate inertia and momentum. So increasing disastrous and catastrophic impacts world wide are unavoidable. The chart does not include forest fires or floods. The AR5 reports that forest fires are increasing, and floods may be increasing.
Extreme weather is most damaging to human population health and their crops, and damages ecosystems.
Obviously global warming causes more heat waves. Most significantly extreme heat on land has continued to increase rapidly 'No pause in the increase of hot temperature' extremes' Nature 2014 article science daily.
It increases drought particularly in already drier regions.
If heat is extreme enough it causes drought by evaporating surface and soil moisture. Global warming increases atmospheric water vapor (warm air holds more water vapor) while the energizing of the hydrological cycle (heat is energy) leads to stronger winds, more heavy rains and flooding. The strength of tropical cyclone-type storms, such as hurricanes, is increased.
As global warming increases, climate extremes are increasing along with the average temperature and climate.
Climate change increased weather extremes are already killing hundreds of thousands of people according to the 2009 Human Impact Report and the 2012 DARA Climate Vulnerability Monitor that estimated 400,000 people are being killed a year. Most presently are killed by the increasing extreme weather in the most vulnerable countries.
Millions of people are being made homeless by climate change increased weather extremes as estimated by the 2012 report of the Internal Displacement Monitoring Center, Global Estimates 2012: People Displaced by Disasters (13 May 2013).
The Global Estimates report reveals that 32.4 million people were forced to flee their homes in 2012 by disasters such as floods, storms and earthquakes. 98% of all displacement in 2012 was related to climate- and weather-related events, with flood disasters in India and Nigeria accounting for 41% of global displacement in 2012.
In November of 2013, Typhoon Haiyan (known as Typhoon Yolanda in the Philippines) set a new record as the most powerful tropical cyclone ever to strike land at 195 miles per hour. Over 6000 people died, many of them in a massive storm surge. With global warming causing rising sea levels and more intense rains, plus the likelihood of more intense winds, disasters like this stand to become more likely. A study by a team from Seoul National University suggests that storm tracks in the Pacific could also change, bringing more typhoons into Korea and China.
CLIMATE EMERGENCY INSTITUTE
The health and human rights approach to climate change
2014 Bulletin of the American Meteorological Society (BAMS) Extreme Events of 2013 (below)
US to 2015