Sunday, 21 October 2007

Positive feedback in global warming...

Most studies indicate that global warming is happening quicker than previously thought.

Positive feedback is probably responsible for some of it. An example will explain how this works:
Arctic ice is highly reflective and sends a good fraction of sun's energy back into spcae. If the ice melts then it is replaced by darker looking water which reflects less light and absorbs more of the incident energy causing additional warming. This warming then melts more ice that then results in still greater absorption of solar energy. And so the cycle goes on, feeding on itself. All the evidence is that the amount of arctic ice is shrinking rather rapidly.

Another example of positive feedback may be the oceans that are vast sinks of carbon di-oxide. Water vapour and carbon di-oxide are two main gases in the atmosphere that prevent energy from escaping from the earth. Warmer oceans create more water vapour and also absorb less carbon di-oxide. This then creates more warming etc.

Recent studies have found that oceans are absorbing only half the amount of carbon di-oxide from the atmosphere now compared with the amount they soaked up 12 years ago. This is too rapid a change and a real cause of worry about a run-away situation resulting...

Need to do something positive...!

Friday, 12 October 2007

Nobel Peace Prize for Climate Change Campaigners...

Climate change campaigner Al Gore and the UN's Intergovernmental Panel on Climate Change (IPCC) have been jointly awarded the Nobel Peace Prize for 2007.

The UN's IPCC, comprising 3,000 leading climate scientists, is the world's top authority on global warming.

The Nobel committee said it wanted to help the world focus on the threat it faced from climate change.

I think it is a good decision and timely. We must be very close to the 'tipping point' when sensible measures to avoid a runaway scenario may not work. Hope common sense prevails.

Tuesday, 9 October 2007

Two extra suitcases and going no where...

Morbidly obese is someone with body mass index (BMI) greater than 40 - acceptable is 20 to 25.

This is like carrying two 20 kg suitcases everywhere you go - travelling or not. What the extra baggage does to the joints is not difficult to guess. The greatly increased risk of a number of cancers, diabetes and heart problems is well documented. And what about BP (and I do not mean British Petroleum!)

This is the worrying trend found by a study of 12000 people over the past ten years. Number of morbidly obese has doubled - probably not too different than the increase in the number of take aways or the increase in the number of TV channels. The waist size is on average 1.5 inches bigger. It is all very worrying...

BMI is calculated by dividing your weight in kg by square of the height in metres.
Underweight is <19, acceptable is 20 to 25, overweight is 25 to 30, obese is 30 to 40.
Where are you?