What is happening to our climate? By Dr William Roberts, Bristol University (some of you will know his mum!)
The packed hall in Tarvin reflected the interest in this subject and the need to disentangle fact from fiction peddled by some world leaders.
What is the difference between weather and climate?
Weather is the short term variations which we remember e.g. the particularly cold day this winter, snow in June, the year when there was a really hot summer (1976 springs to mind!)
Climate is the changes in average temperatures over longer periods typically at least 30 years.
Dr Roberts explained that people had been taking temperature measurements for hundreds of years so there was an abundance of temperature data which had been translated into graphs, both for the UK and globally.
These graphs showed the highs and lows but the shape of the temperature graph was upwards, so the average temperature was increasing. A graph of carbon dioxide emissions over the same period showed the same upward curve as temperature.
Although there have been natural occurrences of global warming e.g. the end of the ice age, these rises in temperature occurred over many thousands of years, whereas climate change over the past 30 years is due to human activities.
Climate change is measured by analysing temperature, rainfall, vegetation and organisms in the oceans.
Dansgaard researched the connection between the “heaviness” of water and temperature. He discovered that heavy water which weighs more the “normal” water was generated by higher temperatures. So analysis of water from ice cores in the artic regions established if and how temperatures had changed over the centuries.
Scientists can try to understand patterns of climate by analysing such data and learning the causes of those changes.
After answering some searching questions on the subject Dr Roberts concluded that clean technologies were the way forward.
Note: Sue Bentley (former President of Whitley WI) is the new Federation’s climate change ambassador and there is to be a week of action on climate change in July.
Mary Highmore ….. Whitley WI PAL