Greenhouse Gas Increases Accelerating

Global average CO₂ concentrations since 2004 (monthly values in red, long-term trend in black). Click here to enlarge. Credit: NOAA




The National Oceanic and Atmospheric Administration announced last week that increases in two major greenhouse gases accelerated in 2007.

Carbon dioxide (CO₂), the primary contributor to global warming, increased by 0.6%, which represents an addition to the atmosphere of 19 billion tons, or 2.4 parts per million (ppm). This brings the total atmospheric concentration to about 385 ppm, an increase of 37.5% from the pre-industrial level of 280 ppm prior to 1850. The annual increases of 2 ppm -- common since 2000 -- are up from 1.5 ppm annually in the 1980s and less than 1 ppm per year in the 1960s.

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Shoveling Out From a Snow Job

At a recent dinner seminar that I attended, upon hearing that I was a Capital Weather Gang member, an otherwise respectable appearing gentleman asked me how global warming could be occurring in light of the "record-breaking cold winter." I must admit that I was a bit mystified at first, since that claim was not at all consistent with any data I had seen.

I soon discovered, however, that the reports of snowfall records which were being broken in certain northern areas from Wisconsin across southern Canada and into northern New England were being spun into another of the seemingly endless series of politically motivated "proofs" that there is no such thing as global warming. Even the NYTi's normally circumspect science writer Andrew Revkin was drawn in to the hype with an article titled, Skeptics on Human Climate Impact Seize on Cold Spell.

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School Colors: Turning Green

DC's Sidwell Friends School was featured this week on The Weather Channel's Forecast Earth program for being the first LEED Platinum certified K-12 school building in the world. Although there are now three more such schools, Sidwell's Middle School is still the only Platinum level building in the District of Columbia. The new building reduces energy consumption by 60% and municipal water consumption by 93%. The use of energy for lighting in particular is only 10-15% as much as that of a comparable building. Energy saving features include:

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Model Muttering

Note: This post is rated "G", suitable for all audiences; does not contain the weather "s" word.


Weather model skill as a function of year, from The Emergence of Numerical Weather Prediction, Peter Lynch, Cambridge University Press, 2006. Chart © ECMWF. Click image to enlarge.



In the nearly 60 years since the modern era of numerical weather prediction began, many orders of magnitude improvements have been made in both computer technology and the formulation and methods of solution of the equations describing the atmosphere. As a result, huge improvements have been made in the accuracy of daily weather forecasts. As good as the models have become, however, it's important to realize what they can and cannot do.

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Some Drops in the Bucket

Moderate drought continues, especially south of the Potomac

Month-to-date % of normal precipitation, from National Weather Service. Click image to enlarge.




Rainfall amounts from today's showers have been generally light across the area, with totals around 0.1" through late afternoon. Thanks to the record-breaking rain at the beginning and reinforcing amounts in the middle of the month, February's official precipitation so far of over 4" will still go down in the official record books as substantially above normal, regardless of what happens by Leap Day on Friday. Counting today, the nine days with measurable precipitation are nearly equal to the monthly average of 9.5.

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Bucket O' Bookmarks: Site for Kids, Teachers

The latest (January) issue of the Bulletin of the American Meteorological Society has a pointer to a new Weather Channel web site for kids. The WeatherED section contains a weather encyclopedia grouped into topics such as Hurricanes and Tropical Systems, Heat Waves, and Winter Storms. A glossary ranges from "absolute humidity" to "Zulu time". A Careers in Meteorology section summarizes job types and shows the resumes of several Weather Channel on-air personalities. Weather games include an interactive forecast which uses Flash technology to create a custom forecast display. Teacher resources (registration required) include "standards-based lesson plans" on several topics for various grade levels (3-5 and 6-10).

Image from The Weather Channel

"Huge Snowfall Shuts Down D.C. Area"

Floral St. in Washington, Feb. 19, 1979. Click image to enlarge. (Photo © Washington Post, via WeatherBook.com.)

The greatest snowstorm in more than half [a] century left the Washington area smothered under at most two feet of snow yesterday -- a magnificent white menace that virtually imprisoned the city and sent road crews battling to reopen streets for this morning's commuters. [Washington Post, page A1, Feb. 20, 1979]

Today is the anniversary of the second-largest Washington snowstorm of the 20th Century. Now known as Presidents' Day I, following the Presidents' Day II storm of 2003, the storm was originally known as the Washington's Birthday storm.

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