It has been well established that over the past several decades' global surface temperature including the sea surface temperatures over most tropical oceans basins have increased.
Within the field of climate science it is well accepted that the most likely cause of the observed increased of global mean surface temperature is a long term increase in greenhouse gases.
Understanding that weather and climate is the combination of sun/heat, air/wind and water/oceans & seas, it is expected that any long term changes due to global warming will affect atmosphere natural disasters.
In increase in intensity of atmospheric natural disasters is measured by the damage and cost to recover from the storm. Cost is affected by societal change, where urbanization has increased population in areas where storms are common as well as technological advances which increase the value of property.
A concrete connection is difficult to make, since there are many contradicting
thoughts, ideas and data. It is easier to establish a link between climate change to change
in averages than to extremes. There are three main lines of evidence , empirical,
theoretical and proxy.
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"Empirical data changes in quality and availability over time - unlike temperature, the pressure inside hurricanes is not something for which we have an adequate centuries-long record, for example. Further, extreme events are by their nature more variable and less frequent, making it difficult to establish patterns.
Theoretical modes also have limitations. While climate models are increasingly refined, they are simplification of an incredibly complex system and are generally not suited to examining either a specific phenomenon or a specific geographical location.
Indirect proxies such as measurement of impacts are complex: non- climate aspects of the data are themselves variable (i.e. the amount of insured property keeps changing), linked to variable climatic phenomena (i.e. there is an element of chance in the location of a damaging event, and infrequent repetition to allow comparison), simply compounding the difficulty of using them as evidence." (Anderson, 2006 pg.5)
Out of all the extremes the an increase in high temperatures is one of the easiest to connect to effects global warming. The combination of a rise in mean temperatures and serve extremes are not consistent with natural cycles. For example the summer of 2003 where the best explanation is climate change. (Anderson, 2006, pg. 6)
Droughts are easily recognizable but global analysis he just recently been able to determine what is caused by climate change vs. natural variability. (Anderson, 2006, pg
Contradicting evidence of the effects of global warming is one of the reasons that disagreements are prevalent and evidence is lacking to prove global warming increase the intensity of natural disasters. For example, global warming has been blamed for stronger and more frequent El Nino's and the increase intensity of hurricanes. When in fact hurricanes travel westward, whereas El Nino brings eastward blowing winds that disrupt storms making for a quiet hurricane seasons. (Abbott, 2006, pg. 345)
The Atlantic multidecadal oscillation (AMO) defined from the patterns of sea surface temperature variability in the North Atlantic once trend has been removed . The AMO is correlated to air temperatures and rainfall over much of the Northen Hemisphere. It is associated with changes in the frequency of North American droughts and is reflected in the frequency of severe Atlantic hurricanes. It makes unclear and exaggerates the global increase in temperatures due to human-induced global warming. (Wikipedia, 2007)
