View Full Version : Is it possible the current spate of hurricanes is linked to global warming?
09-25-2004, 08:23 PM
Florida is about to get hit by the fourth hurricane this year. That's the first time in a century that the same state got hit four times in a year. (Four hurricanes hit Texas in the late 19th Century, I forget what year.) I admit this is most likely just a run of bad luck . . . but is there any chance it's an anthropogenic phenomenon? Something to do with global warming? Any meteorologists or climatologists have a theory?
09-25-2004, 08:53 PM
One theory i read is that hurricanes hit the caribbean and florida in cycles lasting 30 to 50 years. Up untill several years ago we have been in a lul and right now it is returning in full force. The last presence of this cycle was in the 50-60's. Do note that this is a cycle of quantity of hurricanes not intensity.
09-25-2004, 09:07 PM
Every meteorologist that's been on television (the real ones, not the people on the Weather Channel, degreed though they may be) says that it's not global warming but a cycle of warming water in the Atlantic over the last decade following a 30-year period of cooling water. This is probably the cycle that Ludicrous was referring to. This warmer water will stay on for decades more, and will create more and worse hurricanes. The last warming cycle ended around 1964, which is why most people don't remember it. Besides the population of Florida was 5 milllion in 1964 as opposed to 18 million today; the coasts are much more densely built up; and more people are resident year round.
There is a second cause of this year's odd movement patterns, though. The annual high pressure area that sits in mid-Atlantic, known as the Bermuda High, happens to be cited much closer to the U.S. Atlantic coast than usual. In most years it sits way out from shore. Hurricanes curve around it without hitting land.
This year it's closeness pushes the curve farther west, so that the hurricanes can't move north without all those various bodies of land in the Caribbean and southern U.S. getting in the way.
09-25-2004, 09:16 PM
For starters, hurricanes always begin (http://www.weatherquestions.com/What_causes_hurricanes.htm) as low pressure cells forming over warm spots in the ocean. For as long as they are over an area where the water temperature is above a certain level they continue to absorb water vapor and thus gain strength. Once they cross over to an area of lower water temperature, or over land, they start losing strength and eventually dissipate. I once read exactly what the break point temperature is, but I can't quite remember. Maybe 68 degrees, but I'm not sure.
But what needs to be remembered is that this zone where the temperatures are aobve the breakpoint is critical in analyzing the causes of hurricanes. The larger the zone, the more hurricanes you get, and the stronger they are. If the high-temperature zone is 1000 miles across then a storm moving at ten miles per hour could takes several days to cross it, giving it a long time to gain strength. If the high temperature zone is narrow, then storms will only be inside it for a short time, and the result is less power.
Global ocean temperatures have been on the rise (http://www.giss.nasa.gov/research/forcings/altscenario/) in recent decades, most likely caused by global warming. However, I haven't yet found a good discussion of how hurricane formation zones have changed druing that time period. It seems a good question to ask whether they've been getting bigger over the years or not.
09-25-2004, 09:17 PM
This warmer water will stay on for decades more, and will create more and worse hurricanes.
09-25-2004, 10:41 PM
The guy I heard at the National Hurricane Center in Miami said that the total number of hurricanes isn't a lot different this year than the average over time. However, there have been persistent high pressure cells in the northern Atlantic that have provided westerly steering winds that bring them into Florida and the Gulf of Mexico.
09-27-2004, 08:47 AM
I once read exactly what the break point temperature is, but I can't quite remember. Maybe 68 degrees, but I'm not sure.
The minimum tempurature for hurricane development is 80 degrees (http://www.aoml.noaa.gov/hrd/tcfaq/A15.html) with a water depth of at least 150 feet
vBulletin® v3.7.3, Copyright ©2000-2013, Jelsoft Enterprises Ltd.