ForgotPassword?
Sign Up
Search this Topic:
Forum Jump
Posts: 845
Jan 23 07 4:33 PM
Interact
Posts: 8416
Jan 23 07 7:26 PM
Jan 24 07 12:11 AM
Posts: 1871
Jan 24 07 1:47 AM
Quote:One of the difficulties in identifying the causes of the Little Ice Age is the lack of consensus on what constitutes "normal" climate. While some scholars regard the LIA as an unusual period caused by a combination of global and regional changes, other scientists see glaciation as the norm for the Earth and the Medieval Warm Period (as well as the Holocene interglacial period) as the anomalies requiring explanation (Fagan).
Jan 24 07 2:31 AM
Jan 24 07 10:55 AM
Quote:The new Georgia Tech study has now clarified this issue, showing that while hurricane intensity may be substantially influenced by these other factors for an individual storm or storm season, only an increase in sea surface temperatures can account for the long term increase in hurricane strength. Hoyos and co-workers analysed how four different climatic factors -- sea surface temperatures, humidity in the lower troposphere, vertical wind shear and the changes in "zonal" winds with longitude -- varied between 1970 and 2004, based on satellite data for the North Atlantic, West Pacific, East Pacific, South Pacific, South Indian and North Indian oceans. The team used information theory to analyse the relationship between the variables and the number of Category 4 and 5 hurricanes observed, and employed time series analysis to distinguish long-term trends from shorter-term variations. The results showed a clear, positive increase in global sea surface temperatures since 1970, and no sign of any global trends in humidity, wind shear or zonal wind change. "This research supports the hypothesis that the worldwide increase in sea surface temperatures since 1970 is contributing to increase in global hurricane intensity," team member Judith Curry told PhysicsWeb. "The current consensus is that the increase in tropical sea surface temperatures during the last 35 years is attributed to anthropogenic greenhouse warming."
Jan 24 07 12:10 PM
Quote:Some experts persevered in arguing that slight solar changes (which they thought they detected in the satellite record) had driven the extraordinary warming since the 1970s. Most scientists expected that these correlations would follow the pattern of every other subtle solar-climate correlation that anyone had reported fated to be disproved by the following decade or two of data. Even if the contrarians were right, however, greenhouse warming was bound to swamp the solar effects as humanity emitted ever more gases. Willson, the leader of the satellite experts, explained that in the future,"solar forcing could be significant, but not dominant."(58*) The import of the claim that solar variations influenced climate was now reversed. Critics had used the claim to oppose regulation of greenhouse gases. But what if the planet really did react with extreme sensitivity to almost imperceptible changes in the radiation arriving from the Sun? The planet would surely also be sensitive to greenhouse gas interference with the radiation once it entered the atmosphere. A U.S. National Academy of Sciences panel estimated that if solar radiation were now to weaken as much as it had during the 17th-century Maunder Minimum, the effect would be offset by only two decades of accumulation of greenhouse gases. As one expert explained, the Little Ice Age "was a mere 'blip' compared with expected future climatic change."
Jan 24 07 1:18 PM
Jan 24 07 3:12 PM
Jan 24 07 7:14 PM
Jan 24 07 8:31 PM
Jan 24 07 8:56 PM
Jan 24 07 10:21 PM
Posts: 16876
Jan 25 07 2:33 PM
Jan 25 07 2:55 PM
Jan 25 07 3:40 PM
Posts: 1238
Jan 26 07 3:22 AM
Jan 26 07 6:38 AM
Jan 26 07 3:11 PM
Jan 27 07 7:31 AM
Share This