Guy Snelling

Despite on-going enforcement and tightening of international laws intended to reduce global warming, average sea temperatures continue to rise. Convention tells us that pollution from human industry has caused a blanket effect over the Earth, retaining heat and thereby causing Global Warming. Recent research indicates that we may have got this wrong and that reducing pollution is in fact having the opposite effect.

 Scientists in an airship[1] took samples of water vapour from inside clouds over Houston, Texas – one of the most heavily polluted areas in the USA. These samples were then compared to similar samples taken from ‘clean’ clouds over less populated areas. It was shown that pollution particles, or aerosols, cause water vapour to condense more quickly and to form smaller droplets. This process creates denser clouds that allow less light and heat to pass through, effectively lowering the temperature below the clouds.

If the temperature is lower below polluted clouds, why is the average sea temperature rising?

The average sea temperature has been measured by various means, each with its own measurement uncertainty, since late in the 19th century; only since the late 1960s have satellites been available to take measurements by a consistent method. However, a definite trend of increase in temperature can be seen from 1910 onwards, as shown in the following graph[2]:

The industrial revolution took place from 1760 to about 1840 and it would have taken some years for the effects of the change from manual labour to machines to have any effect on sea temperatures. However, as can be seen from the graph, there is a noticeable downward trend in sea temperatures from the late 19th century.

Could it be, then, that the effects of human pollution on the atmosphere actually caused global cooling?  If so, then it is not beyond the realms of possibility that our efforts to reduce global warming by cleaning up the atmosphere are actually having the opposite effect, and that, while we have been taught to see global warming as harmful to our planet, we are really just witnessing the Earth returning to its natural state.

What can we, as staff and students at the University of Pretoria, do to lessen the effects of global warming on the planet?

• Travelling:
  • use fuel-efficient vehicles or hybrids
  • make use of a car pool
  • check your vehicle’s tyre pressure – it saves fuel
  • walk rather than travelling by car
  • cycle to class rather than driving
  • make use of Park and Ride
  • use public transport
• At home:
  • use energy-efficient light bulbs
  • use of energy-efficient appliances
  • turn electrical appliances off at the power point
  • use clothes lines rather than dryers
  • install photovoltaic panels
  • Install a solar water heater
  • insulate your house with fibreglass thermal insulation, ie ‘Think Pink’
• Food:
  • buy local, rather that imported, food brands
  • buy fresh, rather than frozen, foods
  • go to farmers’ markets
  • eat less meat (Meatless Mondays)
  • plant trees

 References:

 [1] BBC operation Cloud Lab circa 2014

 [2] https://en.wikipedia.org/wiki/File:Global_Sea_Surface_Temperature.jpg