How a Warm Earth fueled Hurricane Sandy
- October 31, 2012
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This morning residents of New Jersey woke up and discovered that Hurricane Sandy had turned the garden state into a Michael Bay film. Damages to property, infrastructure and the economy will likely be greater than any other disaster the east coast has seen. Exceptionally powerful computers model weather like this. They’re required because the computations are far more involved then any team of scientists could hope to tackle longhand. Despite that fact you should clear that we understand of the cause of the hurricane. The simple truth is that this tragedy was largely one we brought on ourselves.
Hurricanes are among the most well studied natural phenomenon on the planet. They’re studied because they’re massive and long in duration. They’re studied because they inspire fear in a way only an unstoppable force can, but mostly hurricanes are well studied because they’re the most expensive of all the natural disasters and insurance companies pay fantastic amounts of money to understand them.
The unknowns of climate change are many; ice-melt, sea-level rise, changes to the salinity of ocean water and alterations to the trade winds being just a few that you may have heard of. Reasonable people have constant disagreements on the relative values of these in predicting the way that an altered climatic system works but all research assures us that the layman only needs to understand one simple concept:
The Earth is not an island.
We’ve been aware that the earth revolves around the sun for some 500 years (not that long given that some readers have relatives near 100) so maybe we haven’t gotten used to the idea that it’s always day and always night. 24-hours a day the earth takes on energy from the sun. 24-hours a day it releases that energy on the night-side of the planet. For a very long time the atmosphere has had just enough of the right materials in it to hold some of that energy as heat. This keeps us 40 to 60 degrees warmer at night than if it didn’t. More poorly understood is the fact that the portion of the atmosphere responsible for this is less than half of one percent of the sky. That’s right – greenhouse gasses make up less than this much of the sky:
The ever-so-slight thickening of the atmosphere alters the balance of energy absorbed and released by the planet. The process is analogous to the gears in a car. Rev your engine to 5000 RPM in first gear and you’ll run out of gas as quickly as someone racing around a track with their tachometer in the same spot. We haven’t changed how much energy is being introduced to the system, we’ve changed how the system is dealing with that energy. Now instead of bleeding heat out into space we’re retaining it and all that extra energy has to go somewhere. That “somewhere” is our oceans. Next time you boil water notice how long it takes and how much energy is required to boil even a small pot. Water is “energy hungry” and it holds onto that energy until there’s some good reason to release it. Some good reason like a hurricane overhead.
As Hurricane Sandy formed the Atlantic ocean’s surface temperature is now five degrees warmer than normal. Let that sink in for a minute. The entire surface of the Atlantic ocean averages five degrees warmer.
What does that mean for hurricanes? Hurricanes get their power by feeding on the warm water under them. That means that a warmer Atlantic has a lot more fuel to contribute. How much more? Hard to say for sure but the the number is astronomical. Take the top inch of ocean surface below hurricane Katrina (125,000 sq. miles) then run the math to heat that volume by five degrees. What you get is an amount of energy in that water eight times greater than was released in all the nuclear tests in the history of the world. Take a look at the chart below. Here we have the math behind the storm. What you see is the combined energy of all the nuclear tests ever conducted on earth followed by the energy increase in the top 1″ of water under each of the hurricanes listed.
The New Math:
A five degree rise for just the first inch of ocean, for a static area 900 miles in diameter (the size of hurricane Sandy) requires 95-million terajoules of energy. If we assume it gets used the most efficiently it can be, a ton of coal gets you about 35 gigajoules. That means we’d need a cube of coal .9 of a mile/side to generate the energy needed to heat just that first inch of water five degrees. Now mind you that all that energy is a fraction of the heat being trapped. Just a fraction. We’re going to see a lot more storms get charged up this way.
Of course storms are larger, stronger and more willing to wander north. Of course they’re more damaging. Of course they’re more destructive. There’s simply no comparison between the energy the sun pours down on the earth and what we are capable of generating. Remember, this is only the top inch of ocean surface we’ve compared and we’ve only looking at a static location. Hurricanes uncover far more than the first inch of water. Waves, currents and the storm’s transit from Africa to North America expose a hurracane to awesome amounts of energy orders of magnitude greater than shown here.
But this is no help to the East Coast. New Jersey will be a mess for the foreseeable future. New York City and its transit systems will see spectacular cost overruns in dealing with this part of the climate crisis. We can’t do anything about these problems, but if you’re reading this with fresh eyes, if these comparisons are new to you, please read more and consider how you can be part of the solution.