I have just finished week 2 of Exeter's Future Learn's climate change MOOC. I am still fascinated by what I am learning although I am finding it a bit of a challenge assimilate all the new information. My first output of the week was a tweet conceptualising Snowball earth - when the earth 2.2 billion and 700 million years ago turned into a giant snowball. In an attempt to retain my new knowledge I explained the process to my husband on our walk, how weathering reduced the carbon dioxide in the atmosphere, which cooled the planet, which led to an increase in ice cover, reducing absorption and increasing reflectivity (albedo) and how when the ice reached 30 degrees, the tropics, amplification ran away, resulting snowball earth. Although he he was slightly unimpressed it did not explain why certain parts of the canal were thick with ice despite the weather being milder, I did find this article though ice in lakes and rivers .Walking past industrial relics prompted me to give an overview of how paleoclimatologists use proxy data, tree rings, pollen, coral, ice cores, historical data and ocean and lake sediment to reconstruct past climate conditions, much in the same the way the decaying buildings give us insights into past industrial society.
Today I learned more about aerosols, a topic that is both complex and compelling. 90% of aerosols are produced naturally, different aerosols scatter incoming sunlight, 25% of which is reflected back to space. Bright coloured aerosols reflect e.g. sulphates and dark absorb e.g. black carbon. Most clouds existence is due to aerosols, polluted clouds are darker, pristine clouds are lighter they block the sunlight and have a cooling effect. 5% increased cloud reflectivity could compensate for greenhouse gases but aerosol distribution is different to greenhouse gases so they could not cancel effects as cooling is less than half the effect of greenhouse gases, the impact is therefore regional. The satellite images on the NASA site http://earthobservatory.nasa.gov/Features/Aerosols/ which show the density of greenhouse gases across the planet clearly illustrate the impact of shifting industrialisation on the planet, the heavy blankets across Asia, in comparison to those in North America and Europe where aerosols have declined with the movement of factories and the adoption of clean air strategies. It led me to reflect on how the picture would have looked 50 years ago before this global shift and in the UK before 1956 clean air act began to have an impact. In a way the picture has possibly not changed but just mirrored on the opposite side of the world. In addition, to this the current debating about discussion about the expansion of fracking in the UK has led me to look into this more particularly its impact on the climate. Despite natural gas producing less carbon dioxide it is possible that cheap fuel will increase carbon emissions and there is also a predicted impact on the increase in methane. I found these sites particular helpful.
Climate Coalition
Fracking boom will not tackle global warming - The Guardian Newspaper
