Hurricane Sandy

Post image for No Long-Term Trend in Frequency, Strength of Landfalling Hurricanes

Numerous politicians, pundits, and activists, and even some scientists blame fossil-fuel emissions for the death and devastation wrought by Hurricane Sandy. Such allegations are ideological, not scientific.

As noted previously on this blog, when hurricane damages are adjusted (“normalized”) to account for changes in population, per capita income, and the consumer price index, there is no long-term trend such as might indicate an increase in hurricane frequency or power related to global climate change.

Moreover, 370 years of tropical cyclone data from the Lesser Antilles (the eastern Caribbean island chain that bisects the main development region for landfalling U.S. hurricanes) show no long-term trend in either power or frequency but a 50- to 70-year wave pattern associated with the Atlantic Multidecadal Oscillation, a mode of natural climate variability. 

A new study by Jessica Weinkle (University of Colorado), Ryan Maue (Naval Research Laboratory), and Roger Pielke, Jr. (University of Colorado) dumps more cold water on claims that global warming significantly (detectably) influences hurricane behavior.

The researchers examined data on the number and power of hurricanes making landfall in the five main hurricane basins: North Atlantic, northeastern Pacific, western North Pacific, northern Indian Ocean, and Southern Hemisphere. The data extend back to 1944 for the North Atlantic, to 1950 for the northeastern Pacific, and to 1970 for the other basins. The data for all basins is current through 2010.

Here’s what Weinkle, Maue, and Pielke, Jr. found:  

We have identified considerable interannual variability in the frequency of global hurricane landfalls; but within the resolution of the available data, our evidence does not support the presence of significant long-period global or individual basin linear trends for minor, major, or total hurricanes within the period(s) covered by the available quality data. Therefore, our long-period analysis does not support claims that increasing TC [tropical cyclone] landfall frequency or landfall intensity has contributed to concomitantly increasing economic losses.

Figure explanation: Red bars indicate the number of major (category 3-5) hurricanes, blue bars indicate the number of minor (category 1-2) hurricanes. [click to continue…]

Post image for Sen. Whitehouse Fumes at ‘Climate Deniers’

In a fiery speech yesterday, Sen. Sheldon Whitehouse (D-R.I.) ”calls out” “climate deniers.” In the first half of the speech he goes ad hominem, attacking opponents as “front groups” who take payola from “polluters” to “confuse” the public by selling “doubt” as their product.

First a bit of free advice for the good Senator:

Your team has been playing nasty from day one. It didn’t get you cap-and-trade, it didn’t get you Senate ratification of the Kyoto Protocol, and it’s not going to get you a carbon tax.  

Vilification doesn’t work because biomass, wind turbines, and solar panels are not up to the challenge of powering a modern economy, and most Americans are too practical to believe otherwise.

So by all means, keep talking trash about your opponents. The shriller your rhetoric, the more skeptical the public will become about your bona fides as an honest broker of “the science.”

Okay, let’s examine Sen. Whitehouse’s argument. He accuses skeptics of peddling “straw man arguments,” such as that “the earth’s climate always changes; it’s been warmer in the past.” Well, it does, and it has! Many studies indicate the Medieval Warm Period (MWP) was warmer than the current warm period (CWP). A study published in July in Nature Climate Change concludes the Roman Warm Period (RWP) was warmer than both the MWP and CWP. The Northern Hemisphere was substantially warmer than the present for thousands of years during the Holocene Climate Optimum (~5,000-9,000 years ago). Arctic summer air temperatures were 4-5°C above present temperatures for millennia during the previous interglacial period.

None of this is evidence man-made global warming is not occurring, but Sen. Whitehouse sets up his own straw man by making that the main issue in dispute. What the paleoclimate information does indicate is that the warmth of the past 50 years is not outside the range of natural variability and is no cause for alarm. The greater-than-present warmth of the Holocene Optimum, RWP, and MWP contributed to improvements in human health and welfare[click to continue…]

Post image for Scientists Find No Trend in 370 Years of Tropical Cyclone Data

With Senators Barbara Boxer (D-Calif.) and Frank Lautenberg (D-N.J.) citing Hurricane Sandy as a reason to have another go at climate legislation, to say nothing of the media spin depicting Sandy as punishment for our fuelish ways, it’s useful to look at some actual science.

In a study published in the journal Climatic Change, scientists Michael Chenoweth and Dmitry Divine analyze the history of tropical cyclone activity in the Lesser Antilles from 1638 to 2009. The Lesser Antilles are the string of islands lying along the eastern Caribbean Sea.

The Lesser Antilles intersect the “main development region” for Atlantic hurricane formation, making storm data there “our best source for historical variability of tropical cyclones in the tropical Atlantic in the past three centuries,” the researchers explain.

Using instrumental data on wind speeds going back to 1900 plus wind-force and wind-induced damage reports for earlier periods, Chenoweth and Divine estimate the Lesser Antilles Accumulated Cyclone Energy (LACE) for each year along the 61.5°W meridian from 18 to 25° N latitude.

Storms forming in this area include most that do or could make landfall in the U.S. In the researchers’ words: “About 60% of all tropical cyclones moving from waters off of Africa pass through 61.5°W south of 25.0°N, the remaining 40% either moving north of 25.0°N, dying out or re-curving to the east of 61.5°W.” Chenoweth and Divine note that LACE is “highly correlated” with Carribbean basin-wide Accumulated Cyclone Energy (ACE) since 1899.

So what did they find? In their words: “Our record of tropical cyclone activity reveals no trends in LACE in the best-sampled regions for the past 320 years. Likewise, even in the incompletely sampled region north of the Lesser Antilles there is no trend in either numbers or LACE.” [click to continue…]

Post image for Hurricane Sandy and Global Warming

Both the blogosphere and the mainstream media have been abuzz with commentary blaming global warming for Hurricane Sandy and the associated deaths and devastation. Bloomberg BusinessWeek epitomizes this brand of journalism. Its magazine cover proclaims the culpability of global warming as an obvious fact:

Part of the thinking here is simply that certain aspects of the storm (lowest barometric pressure for a winter cyclone in the Northeast) and its consequences (worst flooding of the New York City subway system) are “unprecedented,” so what more proof do we need that our fuelish ways have dangerously loaded the climate dice to produce ever more terrible extremes?

After all, argues Climate Progress blogger Brad Johnston, quoting hockey stick inventor Michael Mann, “climate change is present in every single meteorological event.” Here’s Mann’s explanation:

The fact remains that there is 4 percent more water vapor – and associated additional moist energy – available both to power individual storms and to produce intense rainfall from them. Climate change is present in every single meteorological event, in that these events are occurring within a baseline atmospheric environment that has shifted in favor of more intense weather events.

Well sure, climate is average weather over a period of time, so as climate changes, so does the weather. But that tautology tells us nothing about how much — or even how — global warming influences any particular event. Moreover, if “climate change is present in every single meteorological event,” then it is also present in ”good” weather (however defined) as well as “bad.”

Anthony Watts makes this criticism on his indispensable blog, noting that as carbon dioxide (CO2) concentrations have risen, the frequency of hurricanes making landfall in the U.S. has declined.

The US Has Had 285 Hurricane Strikes Since 1850: ‘The U.S. has always been vulnerable to hurricanes. 86% of U.S. hurricane strikes occurred with CO2 below [NASA scientist James] Hansen’s safe level of 350 PPM.’

If there’s anything in this data at all, it looks like CO2 is preventing more US landfalling hurricanes.

Data Source: NOAA; Figure Source: Steve Goddard [click to continue…]