Friday, October 26, 2007

35 Mistakes, continued

Mumbai "flooding"
Gore says flooding in Mumbai is increasing, by implication because of “global warming.” It is not. Rainfall trends at the two major weather stations in Mumbai show no increase in heavy rainfall over the past 48 years.

Severe tornadoes "more frequent"
Gore says that 2004 set an all-time record for tornadoes in the US. More tornadoes are being reported because detection systems are better than they were. But the number of severe tornadoes has been falling for more than 50 years.

The sun "heats the Arctic ocean"
Gore says that ice-melt allows the Sun to heat the Arctic Ocean, and a diagram shows the Sun’s rays heating it directly. It does not. The ocean emits radiant energy at the moment of absorption, and would freeze if there were no atmosphere. It is the atmosphere, not the Sun that warms the ocean. Also, Gore’s diagram confuses the tropopause with the ionosphere, and he makes a number of other errors indicating that he does not understand the elementary physics of radiative transfer.

Arctic "warming fastest"
Gore says the Arctic has been warming faster than the rest of the planet. It is not. While it is in general true that during periods of warming (whether natural or anthropogenic) the Arctic will warm faster than other regions, Gore does not mention that the Arctic has been cooling over the past 60 years, and is now one degree Celsius cooler than it was in the 1940s. There was a record amount of snow cover in the Northern Hemisphere in 2001. Several vessels were icebound in the Arctic in the spring of 2007, but few newspapers reported this. The newspapers reported that the North-West Passage was free of ice in 2007, and said that this was for the first time since records began: but the records, taken by satellites, had only begun 29 years previously. The North-West Passage had also been open for shipping in 1945, and, in 1903, the great Norwegian explorer Amundsen had passed through it in a sailing ship.

Greenland ice sheet "unstable"
Gore says “global warming” is making the Greenland ice sheet unstable. It is not. Greenland ice grows 2in a year. The Greenland ice sheet survived each of the previous three interglacial periods, each of which was 5 degrees Celsius warmer than the present. It survived atmospheric CO2 concentrations of up to 1000 ppmv (compared with today’s 400 ppmv). It last melted 850,000 years ago, when humankind did not exist and could not have caused the melting. There is a close correlation between variations in Solar activity and temperature anomalies in Greenland, but there is no correlation between variations in CO2 concentration and temperature changes in Greenland. The IPCC (2001) says that to melt even half the Greenland ice sheet would require temperature to rise by 5.5 degrees C and remain that high for several thousand years.

Himalayan glacial melt waters "failing"
Gore says 40% of the world’s population get their water supply from Himalayan glacial melt waters that are failing because of “global warming.” They don’t and they are not. The water comes almost entirely from snow-melt, not from ice-melt. Over the past 40 years there has been no decline in the amount of snow-melt in Eurasia.

Peruvian glaciers "disappearing"

Gore says that a Peruvian glacier is less extensive now than it was in the 1940s, implying that “global warming” is the cause. It is not. Except for the very highest peaks, the normal state of the Peruvian cordilleras has been ice-free throughout most of the past 10,000 years.

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