National Hurricane Center...

Frank Lansner skrev:
Interessant!

Men jeg er lidt nysgerrig: Mener du at disse vejrforhold kan tilskrives "global warming"?
I så fald: Burde sådanne storme så ikke komme i en periode med "global warming"?
Siden Januar 2007 er temperaturerne jo faldet svarende til et helt århundredes opvarmning, så hvorledes skulle vejrforhold anno 2008, august, kunne kobles til specielt varme tider?

Men jeg er lidt nysgerrig: Mener du at disse vejrforhold kan tilskrives "global warming"?

There is increasing concern that extreme events may be
changing in frequency and intensity as a result of human
influences on climate. Climate change may be perceived most
through the impacts of extremes, although these are to a large
degree dependent on the system under consideration, including
its vulnerability, resiliency and capacity for adaptation and
mitigation;....Improvements in technology mean that people hear about extremes in most parts of theworld within a few hours of their occurrence. Pictures shot by
camcorders on the news may foster a belief that weather-related
extremes are increasing in frequency, whether they are or not.
An extreme weather event becomes a disaster when society and/
or ecosystems are unable to cope with it effectively. Growing
human vulnerability (due to growing numbers of people living
in exposed and marginal areas or due to the development of
more high-value property in high-risk zones) is increasing the
risk, while human endeavours (such as by local governments)
try to mitigate possible effects.

The assessment of extremes in this section is based on longterm
observational series of weather elements.....

The TAR noted that evidence for changes in tropical cyclones
(both in number and in intensity) across the various ocean
basins is often hampered by classification changes. In addition,
considerable inter-decadal variability reduces significance of
any long-term trends. Careful interpretation of observational
records is therefore required.....

Single extreme events cannot be simply and directly attributed to anthropogenic climate change, as there is always a finite chance the event in question might have occurred naturally. However, when a pattern of extreme weather persists for some time, it may be classed as an extreme climate event, perhaps associated with anomalies in SSTs (such as El Niño). This box provides examples of some recent (post-TAR) notable extreme climate events. A lack of long and homogeneous observational data often makes it difficult to place some of these events in a longer-term context. The odds may have shifted to make some of them more likely than in an unchanging climate, but attribution of the change in odds typically requires extensive model experiments, a topic taken up in Chapter 9. It may be possible, however, to say that the occurrence of recent events is consistent with physically based expectations arising from climatechange.

manse42[halvaktiv] skrev:
1: antalet at storme ikke har været stigende og heller ikke antallet af de kraftige. Det er forbedrede observationsmetoden der forskyder billedet.

4: øget vejraktivitet (ekstreme storme) kommer af store temperaturforskelle, hvilket lige netop global opvarmning er ved at udligne.

Alle ved at der har været stor stigning i antal orkaner her på det sidste

We find that, after adjusting for such an estimated number of missing storms, there is a small nominally positive upward trend in tropical storm occurrence from 1878-2006. But statistical tests reveal that this trend is so small, relative to the variability in the series, that it is not significantly distinguishable from zero (Figure right). Thus the historical tropical storm count record does not provide compelling evidence for a greenhouse warming induced long-term increase.

tsk tsk.... de store orkaner kommer af varmt havvand. og det gør global opvarmning ikk ligefrem bedre vel?