Tag Archives: global warming

Ice caps losing water and gravitational attraction

Map of the world showing population density is greater in the regions furthest from the polesI have written previously about sea level rises [see ‘Merseyside Totemy‘ on August 17th, 2022 and ‘Climate change and tides in Liverpool‘ on May 11th, 2016] and the fact that a 1 metre rise in sea level would displace 145 million people [see ‘New Year resolution‘ on December 31st, 2014].  Sea levels globally have risen 102.5 mm since 1993 primarily due to the water added as a result of the melting of glaciers and icecaps and due to the expansion of the seawater as its temperature rises – both of these causes are a result of global warming resulting from human activity.  I think that this is probably well-known to most readers of this blog. However, I had not appreciated that the polar ice caps are sufficiently massive that their gravitational attraction pulls the water in the oceans towards them, so that as they melt the oceans move towards a more even distribution of water raising sea levels further away from the icecaps.  This is problematic because the population density is higher in the regions further away from the polar ice caps, as shown in the image.  Worldwide about 1 billion people, or about an eighth of the global population, live less than 10 metres above current high tide lines.  If we fail to limit global warming to 1.5 degrees Centigrade and it peaks at 5 degrees Centigrade then the average sea level rise is predicted to be as high as 7 m according to the IPCC.

Image: Population Density, v4.11, 2020 by SEDACMaps CC-BY-2.0 Creative Commons Attribution 2.0 Generic license.

Source: Thomas Halliday, Otherlands: A World in the Making, London: Allen Lane, 2022

Planetary Emergency

Global energy budget from Trenberth et al 2009

This week’s lecture in my thermodynamics course for first-year undergraduate students was about thermodynamic systems and the energy flows in and out of them. I concluded the lecture by talking about our planet as a thermodynamic system using the classic schematic in the thumbnail [see ‘Ample sufficiency of solar energy‘ on October 25th, 2017 for more discussion on this schematic].  This is usually a popular lecture but this year it had particular resonance because of the widely publicised strikes by students for action on climate change.  I have called before for individuals to take responsibility given the intransigence of governments [see ‘Are we all free riders‘ on June 6th, 2016 or ‘New Year Resolution‘ on December 31st, 2014]; so, it is good to see young people making their views and feelings known.

Weather-related events, such as widespread flooding and fires, are reported so frequently in the media that perhaps we have started to ignore them as portents of climate change.  For me, three headlines events have reinforced the gravity of the situation:

  1. The publication earlier this month of a joint report by UNICEF and the Royal College of Paediatrics and Child Health that air pollution in the UK so high that it is infringing the fundamental rights of children to grow up in a clean and safe environment; and, under the Government’s current plans, air pollution in the UK is expected to remain at dangerous levels for at least another 10 years.
  2. The warning earlier this month from the Meteorological Office in London that global warming could exceed 1.5C above pre-industrial levels within five years.  In my lecture, I highlighted that a 2C rise would be equal to the temperature 3 million years ago when sea levels were 25 to 35m high; and, a 1m rise in sea level would displace 145 million people globally [according to Blockstein & Weigmann, 2010].
  3. The suspension of construction of the new nuclear power station on Anglesey by Hitachi, which leaves the UK Government’s energy strategy in disarray with only one of the six planned new power stations under construction.  This leaves the UK unable to switch from fossil-fuelled to electric vehicles and dependent on fossil fuel to meet current electricity demand.

I apologise for my UK focus this week but whereever you are reading this blog you could probably find similar headlines in your region.  For instance, the 2016 UNICEF report states that one in seven children worldwide live in toxic air and air pollution is a major contributing factor in the deaths of around 600,000 children under five every year.  These three headlines illustrate that there is a planetary emergency because climate change is rapidly and radically altering the ecosystem with likely dire consequences for all living things; that despite a near-existential threat to the next generation as a consequence of air pollution most governments are effectively doing nothing; and that in the UK we are locked into a fossil-fuel dependency for the foreseeable future due to a lack of competent planning and commitment from the government which will compound the air pollution and climate change problems.

Our politicians need to stop arguing about borders and starting worrying about the whole planet.  We are all in this together and no man-made border will protect us from the impact of making the planet a hostile environment for life.