Home > News > Leakegate: Tropical Storms and a Lying Leake

Leakegate: Tropical Storms and a Lying Leake

2010 March 2

Jonathan Leake is a liar masquerading as a journalist. We’ve known that for some time due to the efforts of Tim Lambert at Deltoid. So it’s no surprise that his latest story opens with another one.

Research by hurricane scientists may force the UN’s climate panel to reconsider its claims that greenhouse gas emissions have caused an increase in the number of tropical storms.


What does the IPCC have to say about tropical storms …?

A synthesis of the model results to date indicates that, for a future warmer climate, coarse-resolution models show few consistent changes in tropical cyclones, with results dependent on the model, although those models do show a consistent increase in precipitation intensity in future storms. Higher-resolution models that more credibly simulate tropical cyclones project some consistent increase in peak wind intensities, but a more consistent projected increase in mean and peak precipitation intensities in future tropical cyclones. There is also a less certain possibility of a decrease in the number of relatively weak tropical cyclones, increased numbers of intense tropical cyclones and a global decrease in total numbers of tropical cyclones.


And from the Summary for Policy Makers

There is no clear trend in the annual numbers of tropical cyclones.


Based on a range of models, it is likely that future tropical cyclones (typhoons and hurricanes) will become more intense, with larger peak wind speeds and more heavy precipitation associated with ongoing increases of tropical sea surface temperatures. There is less confidence in projections of a global decrease in numbers of tropical cyclones. The apparent increase in the proportion of very intense storms since 1970 in some regions is much larger than simulated by current models for that period. {9.5, 10.3, 3.8}


The idea that global warming could be leading to fewer, more powerful storms is not new. As published in Science in 2005 …

Changes in Tropical Cyclone Number, Duration, and Intensity in a Warming Environment
P. J. Webster, G. J. Holland, J. A. Curry, H.-R. Chang
Science 16 September 2005, Vol. 309. no. 5742, pp. 1844 – 1846

We examined the number of tropical cyclones and cyclone days as well as tropical cyclone intensity over the past 35 years, in an environment of increasing sea surface temperature. A large increase was seen in the number and proportion of hurricanes reaching categories 4 and 5. The largest increase occurred in the North Pacific, Indian, and Southwest Pacific Oceans, and the smallest percentage increase occurred in the North Atlantic Ocean. These increases have taken place while the number of cyclones and cyclone days has decreased in all basins except the North Atlantic during the past decade.

Webster finds that fewer storms, more intense storms, with the fewest changes in the Atlantic have occurred in recent decades.

Here is what Nature had to say about their paper:

Fewer but stronger tropical cyclones

Tropical cyclones are likely to become rarer, overall, in response to climate change, but the most severe cyclones are consistently projected to occur more frequently, concludes a Review article published online this week in Nature Geoscience. With the more intense storms comes an increase of precipitation in the storm centre.

Tom Knutson and colleagues from the World Meteorological Organization’s Expert Team on Tropical Cyclones and Climate Change reviewed publications on past tropical cyclone activity and future projections. They concluded that past changes in hurricane activity cannot be distinguished from natural variability, mainly because of incomplete records and large natural fluctuations over time. However, future projections consistently point to an increase in the most severe tropical cyclones as the climate warms further.


And here is the paper in question …

Knutson, et. al, 2010, Tropical cyclones and climate change, Nature Geoscience 3, 157 – 163 (2010)

Whether the characteristics of tropical cyclones have changed or will change in a warming climate — and if so, how — has been the subject of considerable investigation, often with conflicting results. Large amplitude fluctuations in the frequency and intensity of tropical cyclones greatly complicate both the detection of long-term trends and their attribution to rising levels of atmospheric greenhouse gases. Trend detection is further impeded by substantial limitations in the availability and quality of global historical records of tropical cyclones. Therefore, it remains uncertain whether past changes in tropical cyclone activity have exceeded the variability expected from natural causes. However, future projections based on theory and high-resolution dynamical models consistently indicate that greenhouse warming will cause the globally averaged intensity of tropical cyclones to shift towards stronger storms, with intensity increases of 2–11% by 2100. Existing modelling studies also consistently project decreases in the globally averaged frequency of tropical cyclones, by 6–34%. Balanced against this, higher resolution modelling studies typically project substantial increases in the frequency of the most intense cyclones, and increases of the order of 20% in the precipitation rate within 100 km of the storm centre. For all cyclone parameters, projected changes for individual basins show large variations between different modelling studies.

Webster finds that fewer storms, more intense storms, with the fewest changes in the Atlantic have occurred in recent decades.

The IPCC tentatively suggests fewer storms, more intense storms in the coming decades.

Knutson suggests fewer storms, more intense storms in the coming decades.

History (and Tim Lambert) demonstrates that Jonathan Leake is a liar and I confidently forecast more such bs in the coming weeks.


See also Leakegate + The Australian’s War on Science 46, Tim Lambert @ Deltoid.