The most shocking statement in the aftermath of Hurricane Katrina was President George W. Bush’s remark that “I don’t think anybody anticipated the breach of the levees” that protect New Orleans from flooding. New Orleans is a city mostly below sea level, and must be protected by levees to keep water out. Concern that the levees might break in the midst of a powerful hurricane was widespread among scientists, engineers, and emergency-preparedness experts. Yet Bush apparently did not know of these concerns, even days after the hurricane destroyed the levees and flooded the city.
There is a simple fact on display here, one that goes well beyond this particular hurricane, and even this particular president. There is a deep disconnection in American politics between scientific knowledge and political decisions. Bush bears much responsibility for this. He has proven to be one of America’s least knowledgeable presidents when it comes to science — and one of the most ready to turn science into a political issue.
In recent months, Bush undermined biological theories of evolution in favor of Christian fundamentalist dogmas. He disdains climate science and public health science when it conflicts with the beliefs — and interests — of his core supporters. Simply put, Bush’s record on science policy is miserable.
Climate scientists have warned for years that global warming caused by manmade emissions of greenhouse gases will generate more extreme storms. While there is no scientific way to link a particular hurricane such as Katrina to the long-term trend — in the sense that Katrina might have been bad luck rather than a sign of manmade climate change — the energy of hurricanes throughout the world has been rising markedly.
Bush, alas, led an aggressive effort to discredit climate science rather than to respond to its findings. He called for delays in reducing greenhouse gas emissions that cause global warming, which in turn causes the energy of hurricanes to rise.
According to the underlying science that Bush ignores, hurricanes take their energy from the warmth of seawater. That is why hurricanes occur in hot tropical regions, and at the end of the summer months, when the sea surface temperatures are at their annual maximum. Manmade global warming raises not only air temperatures, but sea-surface temperatures as well. Higher sea-surface temperatures translate into more powerful storms in the world’s oceans.
Hurricanes are measured according to three dimensions: frequency, intensity, and duration. The frequency of hurricanes has not changed much, if at all. The big changes are in hurricanes’ intensity and duration.
Intensity measures a hurricane’s force, which includes wind speeds, and there has been some recorded increase. The biggest change, however, has been in the duration of hurricanes: how many days each hurricane lasts.
Duration has risen markedly around the world. The total energy of a hurricane is found by multiplying the intensity of the hurricane by its duration. This, too, has risen sharply, and more is in store as temperatures rise.
Scientists and engineers who work on climate change stress that governments need to adopt two main responses. The first, called “mitigation,” means reducing the amount of manmade climate change.
This can be done by changing the world’s energy system to limit emissions of carbon dioxide into the atmosphere — the main driver of manmade climate change. One option is a shift to non-carbon energy sources, such as renewable energy (solar and wind power) and nuclear energy. Another option is to combine carbon-based energy (coal, oil, and gas) with new technologies that prevent the emission of airborne carbon.
The second response to climate change, called “adaptation,” requires that we ready ourselves for the climate change now underway and the increased climate change to come in future years. This means preparing for hurricanes that are more powerful in both intensity and duration.
An attentive national government would surely have realized that the Gulf region of the United States is more vulnerable to high- energy hurricanes. Indeed, Hurricane Katrina was the third most intense hurricane ever to make landfall in the US. Such a government would have taken more action to strengthen levees.
The Bush administration’s negligence is especially shocking given the remarkable amount of scientific expertise that exists in the US. Somehow, scientists have been pushed aside by political operators. But the US government’s failings are matched in many parts of the world, and certainly in the poorest countries, where scientific expertise is scarce, and where many governments do not have scientific advisory councils to turn to for guidance.
Hurricane Katrina is a wakeup call, not only for the US but for the world. We are entering a period when good science is vital for our survival. On a crowded planet with threats to our climate, oceans, forests, food production, and water supply, and with global travel and high population densities increasing the risk of worldwide disease epidemics, we must turn to the best of our scientific and engineering knowledge to find a safe passage.
Jeffrey Sachs is Professor of Economics and Director of the Earth Institute at Columbia University.
