Global Warming Continued:

Simplest Prediction is increase in global mean temperature.

Role of clouds is crucial Net Cooling or Warming? There is general consensus that cloud cover will increase as the capacity for the atmosphere to retain water increases with increasing temperature.

What does the actual data look like?

All the Data: Global Warming NCDC Document

Long Term Temperature Trends:

• Northern Hemisphere Temperature Trends over the last 100 years
• Southern Hemisphere Temperature Trends over the last 100 years
• World Temperature Trends over the last 100 years
• Summary of Data

Potential Problems:

• Is the pre-1920 data reliable?
• Increasing number of recording stations since 1950 means non-uniform data quality
• Southern Hemisphere is more ocean to land area than Northern Hemisphere
• But, there does appear to be an 0.5 degree Celsius increase per century in the data

Distribution of Temperature trends on the Earth. Where is it getting warmest the fastest:

All the historical data

1953-1973

1973-1993

When positional data is combined with temperature data and time-sliced in this way - it seems clear the Global Warming is occurring. This conclusion was reached by a National Academy of Science panel in Sept. 1995 and is accepted by most.

Temperature Variations with Altitude

What about the US:

Annual US Trends

Max Temperature US Trends

Min Temperature US Trends

Annual Precipitation Trends

Number of Tornadoes

Some Conclusions

Some Internet Resources:

Nice Overview

Comprehensive overview

Another overview

A Dissenting View (not really - this talks about how we are warming the oceans - same problem!)

Journalistic view of the problem Now on to Ozone Depletion Problem:

Ozone Depletion
Oct 30, 1996 Hole size

Oct 23, 1998 Hole Size

Recent years Data 1998 was largest hole measured due to colder than average temperatures which accelerate the depletion process.

But CFC concentrations are now finally measured to be going down.

Long Term Evolution:

Latest Results (9/1/96 - 10/14/96)
Latest Results (9/1/97 - 10/14/97)

Overview:

• Location of Ozone Layer

• Ozone Destruction Mechanism

• Balance in the Stratosphere

• Annual Data on Ozone Levels

• Oct. 15 Annual Data on Ozone Levels

• Annual Ozone Hole Size Data

• Annual Minimum Levels

• Switzerland Annual Data

• MPEG Animation of 1994 Hole

• A Bigger Animation

• Ozone Mythology

1995 Hole data:

Why do we see the hole in the Antarctic Spring?

Chlorine from CFCs is stored on stratospheric cloud surfaces during the long polar night and then released to attack ozone when the sun returns in spring. The process involves a series of unusual chemical reactions taking place at temperatures as low as -85 degrees C (188K). Normal ozone levels are restored in the summer when the Antarctic atmosphere, isolated during the winter inside a cold "polar vortex", becomes mixed with ozone-rich air from other latitudes.

Expectations for this Spring (i.e. right now)

The Antarctic spring of this year is arriving, and with it the annual depletion of ozone within the south polar vortex. In recent years, the destruction of ozone within the lower stratospheric region from 14 to 20 km has been virtually total.

Where are we Now?

Internet Resources Relevant to the Ozone Problem:

• Ozone Hole Image Archive
• Canadian Weekly Ozone Watch
• Ozone Page from Sweden; nice collection of references
• EPA Straospheric Ozone Page
• What about Bromides?
• Ozone Reality Check

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