1 just the basic facts

For the record: here are the current major points about climate change that I understand that are most relevant to me and my kids here in Australia. First I’ve summarised some major points about what will happen with a 4 degrees C rise. Then I list some key aspects of  what will happen with a 2 degrees C rise.

Without significant efforts to abate the release of climate change gases, most projections are of a 4 degrees increase by 2100. Global average temperatures have already risen by over 1 degrees C and 2 degrees C is likely to have dangerous effects. Parties to the Paris Agreement seek to limit the global average temperature rise forecast for 2100 to 2 degrees C.

4 degrees C rise:

little feetMost projections are of a 4 degrees increase by 2100 which will lead to (source 1):

  • much of the tropics becoming unlivable
  • sea-level rise of meters guaranteed (leading to mass migrations of people across the globe)
  • regular extreme heatwaves in most part of the world in summer
  • reduced global food security

While poor people will be hardest hit, such a change will impact people in Australia significantly.

2 degrees C rise (with contrast to a 1.5 degrees C rise):

Signatories to the Paris Agreement (Source 2) commit to using their best efforts to limit the increase in global temperature that will be reached by 2100 to no more than 2 degrees C, preferably closer to 1.5 degrees C.

A recent key study by the European Geosciences Union (Source 3 and 4) highlighted several key detrimental outcomes associated with a 2 degrees C increase instead of a 1.5 degrees C increase (Source 5). these include:

  • Heat-wave duration, rainstorm intensity and sea-level rise would be roughly a third greater for a 2 degrees rise compared with a 1.5 degrees rise. Furthermore, it must be noted that sea level is likely to continue rising long after air temperature is stabilized) This continual rise due to warm sea temperatures surrounding the ice (rather than ice melting from the top of glaciers) is particularly concerning and hard to predict the possible full extent of.
  • There would be a significantly greater impact on certain basic crops such as soy and wheat.
  • Tropical coral reefs would be basically lost completely. An increase from 1.5 to 2 degrees C takes away the chance for reefs to recover from climate change induced damage so we lose them completely.
  • The Mediterranean area’s fresh water supply (i.e. rainfall runoff) would be muh less : There is likely to be (9% less fresh water available than baseline (they use 1986–2005 as their baseline or reference period) for a 1.5 degrees C rise in temp). This would double (approximately 17% less fresh water available compared to baseline) for a 2 degrees C rise.

It is very concerning and some analysis forecasts that we will cross the 2 degrees C threshold as early as 2036 if we can’t make serious efforts to reduce our carbon usage. That’s only 20 years away. My Lucinda will be 28 and my Stella 26! (source 6). With this key threshold looming so close, you can see why leading climate change voices are urging significant action (source 7) in the three years from June 2017.


  1. http://www.worldbank.org/en/news/press-release/2012/11/18/new-report-examines-risks-of-degree-hotter-world-by-end-of-century
  2. The Paris Agreement: http://unfccc.int/paris_agreement/items/9485.php
  3. http://www.earth-syst-dynam.net/7/327/2016/
  4. http://www.egu.eu/news/230/15c-vs-2c-global-warming-new-study-shows-why-half-a-degree-matters/
  5. https://climate.nasa.gov/news/2458/why-a-half-degree-temperature-rise-is-a-big-deal/
  6. http://www.scientificamerican.com/article/earth-will-cross-the-climate-danger-threshold-by-2036
  7. https://www.nature.com/news/three-years-to-safeguard-our-climate-1.22201

Back to: climate K.I.S.S.

Image credit: Amanda Jordan