The New York Times has an interview with Kerry Emanuel
a climatologist who shook the establishment with his Nature paper that argued for a statistical correlation between temperature and hurricane intensity. The Atlantic 2005, the most active season for storm formation, Accumulated Cyclone Energy and number of storms to reach hurricane status - topping records that had stood since the 1930's in one case - makes a powerful anecdotal argument that the link is not only real, but here.
[Science, economics and art do indeed meet from time to time, at the same time that Emmanuel was watching Katrina grow into the nightmare storm, I was composing a string quartet inspired by "The Year of Storms"]
Hurricane activity does go in cycles, and even with human generated global warming, it will continue to have strong, weak and average years. 2005 was a knock the cover off the ball year for the Atlantic season, because of three factors. The first is that the band of tropical winds that shear apart fledgling hurricanes was at a low ebb. The second is the unusually high sea surface temperatures in the Gulf region, and the third is the development of a secondary basin of formation - in the north eastern Atlantic, which spawned a series of storms, one of which was still alive on New Year's Day. These combined to make 2005 the Barry Bonds of storm seasons. "You can't touch this."
However, the relationship between global warming and hurricanes is not made by one season, but by a long term correlation between storm activity and temperature. Emmanuel's paper was written in 2004, and published before there was a Katrina.
This relationship shows something very important: namely that global warming effects are not off in the distance, to be paid macro-economically by people who aren't even born yet - but instead it will strike to excess with gradually increasing force over the coming decades. The additional strength of hurricanes that Emmanuel predicts does not include the possibility of a vonSchelling effect - that is changes in storm tracks. Including such an effect would mean that no only would there be more, and stronger, storms, but also more of them would make landfall. "Fish spinners" as extreme weather fans call storms that stay far out to sea, are not as much of a danger as large landfalling storms.
The pressure to do something is clear, even to those who are not entirely convinced of the scope of global warming, Prof. Emmanuel states:
It's always struck me as odd that this country hasn't put far more resources into research on alternative energy. Europeans are. France has managed to go 85 percent nuclear in its electrical generation. And the Europeans have gotten together to fund a major nuclear fusion project. It almost offends my pride as a U.S. scientist that we've fallen down so badly in this competition
This is from someone whose political leanings are conservative.
The interview also points to another important point, namely that US building patterns are making a bad thing, worse:
Disaster specialists will tell you that part of the increasing lethality of land-falling hurricanes isn't related to nature. A lot of it has to do with human activity. We're moving to the coasts in droves, like lemmings.
We're building waterfront structures there that aren't necessarily strong. We're taxing the infrastructure and paying a big price for doing that.
What will compound the storm problem is the subject of Kenneth G. Miller and a November article in Science which reports that sea levels are rising at twice the rate of the 19th century. This means that cities such as New Orleans are experiencing not just greater tropical storm risk, but higher storm surges.
This means that areas that are currently on the edge of inhabitability, are destined to become part of the fight between water and land. Combined with the settlement of beachfronts - that is a larger and larger popualation that wants to be "away" from the world, and is willing to take more and more risk to get it, means that much of where we are developing infrastructure is destined to be roads to nowhere.
But that is not the panic button. Instead, recent evidence shows that a previous round of natural global warming caused massive shifts in ocean currents:
An extraordinary burst of global warming that occurred around 55 million years ago dramatically reversed Earth's pattern of ocean currents, a finding that strengthens modern-day concern about climate change, a study says.
The big event, the Palaeocene/Eocene Thermal Maximum (PETM), saw the planet's surface temperature rise by between five and eight degrees C (nine and 16.2 F) in a very short time, unleashing climate shifts that endured tens of thousands of years.
This sets up the possibility of a "rapid disequilibrium" - where climate changes feed into other climate changes that push the median temperature in the same direction. That is, a positive feedback loop where carbon dioxide driven global warming drives hydrologic cycle climate shifts, which in turn reduce the carbon dioxide sinking of the environment, creating more global warming. This only ends when life adapts to the new patterns and begins sinking carbon again. That happens in that long run in which we, our children and several generations of their offspring, and our civilizations, are all dead.
In summary - the evidence is piling up that global warming is here, that it is altering the distribution of water - and water is where the action is, because it stores, transports and delivers the heat that the earth stores up. The effects that are being observed include more violent tropical cyclones, rising sea levels, and potentially shifts in ocean climates. This research is solid and published in peer reviewed journals, often by scientists who have not previously been associated with more dire predictions on global warming.
The response is carbon neutrality - to move away from burning hydrocarbons and coal for energy. Carbon is a rock, most of it should be in the ground. Carbon neutrality means finding a pervasive series of economic substititions - nuclear for coal, wind and solar for natural gas, electrical transport in place of gasoline transport of energy, microgrids for long distance power generation and distribution, new economic systems which reward different kinds of economic activity, smoothness over power as a virtue in automobiles.
The other part is to begin realizing that unplanned growth is not a virtue, but, instead, a vast search for underpriced externalities. That's econospeak for mugging your grandchildren to buy your beachfront bunglo. Emphasis on bungle.