Climate change - not as complicated as you might think

Presented at Nerd Nite Melbourne, April 2014. See video recording here: https://www.youtube.com/watch?v=3qVp97VQQSs

Transcript

1. Not as complicated as you might think… Damien Irving PhD candidate University of Melbourne
2. Climate change… ž  What is it? ž  How do we know it’s happening? ž  How do we know it’s our fault? ž  What will the future climate look like? ž  Why aren’t we doing anything about it? ž  As individuals, what can we do about it?
3. What is it? The Greenhouse Effect
4. What is it? Problem: Greenhouse gas concentrations are on the rise…
5. What is it? Consequences of trapping extra energy…
6. What is it? Surface temperature is only one of many indicators…
7. How do we know it’s happening?
8. How do we know it’s our fault? ž  How  do  we  know  that  we  put  that  excess   carbon  dioxide  in  the  atmosphere?   —  Historical  records  of  human  ac8vity     —  Lighter  isotopic  composi8on  of  atmospheric  carbon     —  Decrease  in  atmospheric  oxygen  (combus8on)   ž  How  do  we  know  the  excess  carbon  dioxide   has  caused  the  rise  in  global  temperature?   —  Our  knowledge  of  the  Greenhouse  effect   —  Our  knowledge  of  the  Earth’s  climate  history   —  Nothing  else  makes  sense   —  Climate  modelling  
9. How do we know it’s our fault? Climate model simulations: with (pink) & without (blue) humans
10. What will the future climate look like? ž  Easy  projec8ons  (high  confidence)   —  Temperature   —  Sea  level   —  Ocean  acidity   ž  More  difficult  projec8ons  (lower  confidence)   —  Rainfall   ◦  Storms,  tropical  cyclones  etc  
11. What will the future climate look like? Projected changes in rainfall
12. Why aren’t we doing anything about it? ž  We can emit 565 more gigatones of CO2 to stay below 2°C warming ž  Fossil fuel companies have 2,795 gigatons in their reserves
13. As individuals, what can we do about it? Westpac divestment, 8 March 2014
14. ž  What is climate change? —  The trapping of extra energy from the sun ž  How do we know it’s happening? —  We measured it ž  How do we know it’s our fault? —  Some cool scientific detective work ◦  Basic concepts from the 1800s, lighter carbon, decreasing oxygen, computer climate models, historical records, … Conclusions
15. Conclusions ž  What will the future climate look like? —  Hotter, higher seas, more acidic oceans —  Wet get wetter, dry get drier ž  Why aren’t we doing anything about it? —  Money / vested interests ž  As individuals, what can we do about it? —  Don’t be an individual - get involved in the community/movement ◦  e.g. divestment, rallies