Climate Change - Present Status & Future Prospects: Talk at WES (Scotland)

Index of Blogs and Courses

 It was a pleasure to talk to the Scottish branch of the Women's Engineering Society on Sunday 31st August about Climate Change - where we are just now and what might be happening in the coming decades?  In the following, I am publishing the slides used for the talk with some minor additions.  Virtual meetings provide welcome break from the isolation created by Covid-19; I believe that this is a great way to communicate science in the community and I hope to use this medium much more in the future. 

The slides form the complete talk.  Commentary between the slides provides further explanation and the links are generally to websites where more detailed discussion of the topic is available.

Please click on a slide to see its full page image

 Slides:

Often people are confused about the difference between weather and climate.  Weather at a particular location describes atmospheric conditions at an instant in time and is highly changeable, while climate is the mean conditions over a long period of time and refers to an extended region.  For details click here. 

The indicators point to a warming world. For example, water expands when heated.  An increase in the sea surface temperature will result in increased volume of water, and sea levels will rise. Similarly global warming will result in a loss of ice in the Arctic Ocean and from the ice caps on mountains where ice will melt due to higher temperatures. Note that mountain ice-melt provides fresh water for drinking and irrigation to a large fraction of the world population and if these glaciers eventually disappear then it will be catastrophic for people downstream - it is expected that by the year 2100, the glaciers in the Himalayas will be reduced to one third of their present size - 2 billion people depend on the fresh water from the glaciers. 

For a detailed discussion of the loss of biodiversity, please click here.

The rate of population increase has dropped considerably in recent years, and it is expected to fall to 0.1% annual increase by the year 2100.  That still means that the population will double every 700 years and could reach more than 20 billion by the year 3000. One has also to deal with all the problems created by inverted population pyramids etc!

While the rich countries caused most of the emissions, the fast developing economies of China, India, Brazil and others are consuming resources at a higher rate than before - these countries represent a much larger population block and it seems unlikely that consumption and hence emissions will start to go down anytime soon.

While solar and wind are the most promising alternative energy technologies just now, and they have helped to cover the additional global energy demand of the past decade, it is difficult to see how they can replace fossil fuels to meet the full global  energy use.  Both solar and wind are excellent for producing electricity - but technologies need to be developed for electrification of transport, manufacturing etc. 

C-14 is the radioactive isotope of carbon that has a half-life (half of the amount present decays) of 5730 years. Plants and animals buried under soil/mud or under water, 200 to 300 million years ago, got converted into fossil fuels.  Obviously, because of the long elapsed time, fossil fuels are totally depleted in C-14, and CO2 produced by burning them has no C-14 in it.  On mixing with the CO2 already present in the atmosphere, the amount of C-14 in a given volume of CO2 will be reduced.  Please click here for a detailed discussion of this topic.

The above three slides are adapted from a recent 2019 study published in nature.com. Please click here to access the full paper. 

The following slides briefly describe the new technologies that are being considered for removing CO2 from the atmosphere - CO2 that is already there.

More details may be found here, here and here.

Post Script: 

Climate change has never been taken seriously by most world governments, and suitable actions were not taken in time to control climate change and mitigate its worst effects.  Even now, when it is obvious that the effects of global warming are seen in frequent weather events, loss of ice sheets in Greenland, sea level rise etc., there is no indication that climate change is being taken seriously - one needs to consider the situation as climate crisis, and treated as such.  The example of the ongoing Covid-19 pandemic stands out when the world governments quickly found 10 to 15% GDP to fight the pandemic.  Twenty years ago, spending 1% of GDP would have been sufficient to control and mitigate the effects of climate change.

Similarly, good education about climate change would create much needed awareness among the general populations, and they will be more motivated to change their lifestyles and consumption habits.  No serious action by the people in power has been apparent and valuable time is being lost.  The longer we wait for sensible actions to start, the more extreme and costly measures will be needed.  There is no sign that things are going to change soon.

One might feel that technology will help to solve any difficulties that climate change might present in the future.  After all technology has always come to rescue in the past. I hope things turns out to be this way - although it would be far better if one could approach the looming threat of climate crisis in a rational way. There is too much at stake.