Snowball earth, proxy data and aerosols

I went for a local Sunday walk with my husband yesterday. We don't live in the country although the country is not far away.  We, do live pretty close to 2 major industrial canals, the Caldon and the Trent and Mersey, the picture here is of Westport man made lake and nature reserve, which was the turning point of our 9 mile circular walk. The route is punctuated with decaying delights from Stoke-on-Trent's Pottery Industry, including an infamous bottle oven.

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

Climate...Change Change Change

I have just started a MOOC being running by the University of Exeter via FutureLearn. I have decided this year I want to know more about what is going on with our environment in more detail, specifically our climate. I have always been fascinated by weather, possibly because I live in the UK, also because I live in a Northern part of the midlands, where we get a lot of rain and the temperature is slightly lower to our neighbours as it is relatively elevated, although on cold clear nights temperature inversion takes place because of clear air drainage. Additionally, I am concerned about the amount of old tech we are all stock piling and our need to change our tech on a regular basis, which adds to the stock pile and in turn has an adverse effect on the environment.  

I have just finished the test for the first week and I was a little bit shocked on my first attempt when I got zero, surely I must have learned something. On my 2nd attempt I realised that I had not submitted my answers for each question, reassuringly my mark was infinitely improved on the 2nd. attempt.  I have had to adopt a slower learning process as there is a considerable factual detail that needs to be understood, unlike social theory which I am more familiar with which requires more interpretation. The following is an overview of what I learned in the first week.

Principles that explain climate change
It appears the greenhouse metaphor is not the best metaphor for explaining climate change, for example, what really heats a greenhouse up is the prevention of air flow stopping the loss of heat by convection. What keeps the earth warm is the presence of greenhouse gases in the atmosphere that absorb heat radiation and re-remits some back to the surface, although is commonly known as the greenhouse effect the gases are more like a blanket, trapping heat and radiating some back. Majority of short wave radiation from the sun reaches the earth's surface and is called albedo. Ice and snow have a high albedo because they reflect a lot of radiation other surfaces e.g. ocean absorbs a lot of radiation and have a low albedo. The earth reflects 30% of sunlight from space the blanket of gases keeps the earth warm. Although Carbon Dioxide is identified as the most important green house gas water vapour is responsible for keeping the planet warm. Other greenhouse gases are methane, ozone and nitrus oxide.

Climate
Weather is the elements we see daily. Climate is change over time usually around 30 years.  A climate system is created by different interactions how the atmosphere interacts with ocean, ice sheets, land mass and vegetation. Sun also drives climate the atmosphere stops heat escaping. Climate is a system with 5 key components, atmosphere, hydrosphere, biosphere, cryosphere and lithosphere. There are a series of cycles interactions between the cycle that powers the climate.  For example the water cycle

1. solar radiates cause water to evaporate from hydrosphere and biosphere e.g. plants
2. water vapour condenses in the atmosphere to form clouds
3. water returns to the earth through precipitation snow
4. Water returns to hydrosphere or cryosphere if frozen as snow
5. sunlight on cryosphere and melt snow or transform directly into vapour process called sublimination from ice sheets, glaciers etc.

Cycles that connect components create feedback loops - closed loops of cause and effect. There are 3 feedback loops determine state of climate
1. water vapour:
Evaporation occurs when solar radiation heats the surface of bodies of water. Water evaporated transformed from liquid to a gas stored in the atmosphere. Molecules of water vapour absorb heat radiation from earth causes to vibrate. These re-emit heat radiation some of which comes to the earth's surface causing further warming. This increases amount of evaporation in an amplifying process causing positive feedback.
2. ice albedo
Where there is a lot of sea ice e.g. arctic much of the solar radiation reflected back into the atmosphere, the ocean reflects but tends to absorb more, where open water is exposed there is more absorption of sunlight as heat going into the ocean which will melt more ice
3. radiation
Important for regulating climate. Example of negative feedback. As body warms it gives off radiation and cools down. Stefan Boltzmann/Planck effect.

Climate is a systems that self-regulates as a result of positive and negative feedback, linking together different components. 

The above the illustrates what I have learned in the first week. For me the most important themes were the blanket effect, the difference between climate and weather and the feedback loops in particular ice albedo and the fact that sea absorbs more solar radiation and ice reflects back. I did find understanding the detail for each of the aspects challenging in particular the feedback loops, I have a sociological background not a technical background although some parts of my work are technical. I have almost had to change my approach to learning understanding factual information rather interpreting. As a result of what I learnt about climate change I did look at how the UK's climate is changing, that there will be more extremes of weather in our changeable climate e.g. wetter milder winters hot drier summers in the long run. The met office was quite helpful http://www.metoffice.gov.uk/climate-guide. Having a combination of videos, articles and activities to reflect I think has helped develop my understanding of what sometimes I have found quite complex.