Wednesday, March 24, 2010

Extreme Weather

There is good evidence to indicate that we are experiencing the dramatic weather effects of climate change. This winter, global warming skeptics put their ignorance on display when they used the record setting snowfalls in Washington to mock those who accept the scientific evidence on human driven climate change.

As an homage to yesterday's World Meteorological Day, and as a rebuke to global warning deniers, here is a brief summary of some of the data on extreme weather events and trends.

Although there is a statistically significant increase in the number of severe weather events, they are also attributable to increased reporting due to an increasing and expanding population.

It is easy to point to isolated events like Hurricane Katrina in 2005 and a deadly heat wave in Europe in the summer of 2003, however to establish a trend, larger amounts of data must be factored over time.

Ferocious storms are consistent with forecasts that a heating planet will produce more frequent and more intense weather events. Thomas Knutson and Robert E. Tuleya of the NOAA stated in 2004 that warming induced by greenhouse gas may lead to increasing occurrences of highly destructive category-5 storms.

Planet wide, the weather has become remarkably unpredictable, however, it may be more accurate to refer to global weirding as opposed to global warming. Increasing temperature is likely to lead to increasing precipitation, but there will be differing effects depending on where you live.

One intrepid Fox news reporter tried to refute global warming by referencing the cold weather experienced in the Northern Hemisphere early this winter. He remarked that even India had experienced unprecedented cold that killed dozens of people.

Despite the Fox reporter's unsubstantiated theory, valid evidence of global climate change is culled from scientific investigation which include comparative studies of data sets over protracted periods of time.

Scientific evidence for global warming comes from several diverse sources. The instrumental temperature record, melting glaciers, rising sea levels, and decreased snow cover in the Northern Hemisphere all offer hard data supporting global warming. Aggregate data focused on night-time temperatures and winter warming offer some of the best evidence of the global warming trend.

It is clear that 2009 was the hottest year in recorded history in most parts of South Asia and Central Africa. The National Oceanic and Atmospheric Administration reported in September that the world's ocean surface temperature was the warmest for any August on record, according to a preliminary analysis based on records dating back to 1880.

The United Nations' weather agency, the World Meteorological Organization (WMO), reported that the last decade was on track to become the warmest since records began in 1850 and 2009 could rank among the top-five warmest years.

Guo Hu, the head of the Beijing Meteorological Bureau, linked extreme weather conditions to unusual atmospheric patterns caused by global warming. "In the context of global warming, extreme atmospheric flows are causing extreme climate incidents to appear more frequently.

In October 2005, The New England Journal of Medicine studied the wide-ranging health effects of extreme weather. Variations in climate, including floods, droughts, and other extreme weather events, influence the range and transmission dynamics of infectious diseases.

The World Meteorological Organization (WMO) and the US Environmental Protection Agency (EPA) have linked increasing extreme weather events to global warming.

The Intergovernmental Panel on Climate Change (IPCC) shares the WMO's assessment. According to IPCC (2007a:10), "[most] of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in [human greenhouse gas] concentrations".

IPCC (2007a:8) has also predicted that in the future, over most land areas, the frequency of warm spells or heat waves will increase. They also predict other changes including increasing areas of drought, increasingly intense tropical cyclone activity and increasing incidences of extreme high sea level.

The WMO has indicated that future climate changes will include further global warming and a probable increase in the frequency of some extreme weather events.

The evidence supports the contention that human activity is contributing to increasing incidences of extreme weather and this is likely to worsen. The question is, what are we going to do about it?
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Green Dissent (Part 2)
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