Tom Fuller's Interview with John Christy

By -
Here is an excellent interview with a well-respected atmospheric scientist. Please note the comments with regard to the accuracy of global climate models (GCMs). In the comments section, one questioner asks why we don't receive short term (seasonal) forecasts from the GCMs. I can answer that one: Because they are horribly inaccurate. That is the dirty secret of the climate models. They can't make accurate forecasts for 90 days but we are supposed to believe their forecasts for 90 years.

Comments

  1. Joel GratzJuly 14, 2010 at 8:53 AM

    Mike - I agree with your skepticism of the climate models and their accuracy, but I agree for a different reason. Short-term weather prediction models are fundamentally different than long-term climate models, so you can't directly compare them (i.e. a 90 day forecast by a climate model). However, the amount we don't know about climate dynamics and feedbacks is staggering, so it's likely that the climate models are way off simply because we have more knowledge to acquire. However...Christy's point about being ready for historical weather/climate extremes is a good one. We're not adequately prepared to deal with floods/heat/hurricanes/etc that have happened before and will happen again, so putting all our efforts to preventing a potential scenario 100 years in the future may not be the best use of resources...

    ReplyDelete
  2. Mike SmithJuly 14, 2010 at 10:05 AM

    Joel,

    I see three items here, so allow me to comment on each.

    The meteorological "guts" of the climate models are the same as the day-to-day forecast models except at lower resolution and more parameterization. If you go back and look at Hansen's 1988 testimony, he said his model indicated that "lower Manhattan would be under 3-4' of water by 2000" -- a testable forecast that busted. The IPCC climate model forecasts have consistently overforecast the amount of warming. If they cannot get relatively short term forecasts (ten months or ten years) right, I cannot think of a scientific reason why their 90-year forecasts (2100) should be treated as if they had perfect accuracy.

    You are correct that what we don't know is staggering! This includes things that aren't significantly important in 24-48 hour forecasts (arctic ice albedo, ocean temperatures, etc.) and non-atmospheric influences like volcanoes, sunspots, etc. This is a second reason to take the climate models with a huge grain of salt.

    That said, you and I are in complete agreement about historical weather and climate extremes. There is much more to be gained from mitigating things that are right in front of us ( http://meteorologicalmusings.blogspot.com/2010/07/where-is-big-environment.html ) than trying to "fix" the climate 90 years from now by any rational cost/benefit analysis.

    Thanks for the comment, Joel.

    ReplyDelete

Post a Comment

Popular posts from this blog

Hilary's Forecast Path Shifts West; Updated 9:20am PDT

By -
Image
The forecast path of the center of Hilary has shifted a bit to the west. This increases the threat to the Southland, especially in terms of flooding.  Rainfall Note the heavy rains are forecast for Los Angeles County. Serious flash flooding may result. Because the forecast path has shifted to the west, that increases the threat of serious flooding in Los Angeles County north into Yosemite and the southern Sierra. It lessens the threat in Utah and western Arizona. While the threat of widespread flooding in Utah and Arizona lessens, note that some thunderstorms with localized heavy rain show up on the map.  In Nevada, the more western path increases the risk of serious flooding around Mt Charleston and into the central part of the state.  Here is the updated  (9am PDT) flash flood risk map. Wind There are already about 40,000 people without power in California, mostly in the center of the state.  The maps above are the peak gusts forecasted with the storm. The highest winds, in general,
Read more

Dangerous Travel Conditions - People Reportedly Stranded

By -
Image
-- Note, more current info available. Scroll up. --- Updated Information as of 8am PDT You are risking your life if you attempt to travel through the purple area.  While the rain has not begun in coastal California, I would urge you to use this time to make any preparations. Power outages have occurred already in southeast California. Here is the latest radar as of 7:55am PDT. As of 6:40am PDT , the radar indicates moderate to heavy rain falling over desert areas of Southern California and far western Arizona (click to enlarge).  Rainfall amounts for the 24 hours ending at 7am PDT show more than two inches have already fallen. There are reports from reliable sources that roads are already washed out and that people are stranded in isolated parts of the desert.  Below is a high-resolution computer model's rainfall forecast from 5am PDT to 11pm PDT Sunday. More than a foot of additional rain is forecast to fall. This will lead to catastrophic flooding.  Here is a map of current watc
Read more

Update on Tornado and Wind Potential; 12 Noon PDT

By -
Image
There was at least one tornado and at least one funnel cloud yesterday.  --- original forecast --- Hilary (the swirly symbol) continues to move NNW paralleling the coast of Baja California, Mexico. The area outlined in red has a significant risk of tornadoe s the rest of the afternoon.  Below is a list of peak wind gusts so far.  Peak winds may increase farther north as the afternoon progresses.  Addition at 12 noon PDT: Sure enough, winds have increased.  Note: If you are in the San Diego area, I recommend not  traveling east on I-8. Heavy rains may cause flash flooding that will involve the highway. 
Read more