Another appeal to reason: dont try to look cool

1
Another appeal to reason dont try to look cool

• Dr Simon Dietz
• London School of Economics

2
The real state of climate science
3
Climate facts

• Effectively certain (i.e. beyond reasonable
  doubt)
• Burning fossil fuels is the largest single cause
  of emissions of CO2
• Atmospheric CO2 concentrations are increasing,
  and have done so since the beginning of the
  industrial revolution
• CO2 is a greenhouse gas
• Global warming is occurring at rates that are
  unprecedented in human history (and beyond)
• The rate of warming observed is consistent with
  the observed changes in greenhouse gas
  concentrations (and well founded estimates of the
  greenhouse effect)
• What more could one reasonably ask for?

4
Remaining uncertainties

• The things we still dont know
• The mechanisms and magnitudes of feedbacks
  between greenhouse gas concentrations and
  radiative forcing, like clouds and changes in
  the carbon cycle
• The precise magnitude of natural effects
• The precise extent to which observed warming is
  man-made
• The key point these could just as well make
  things worse than expected as better

5
The real range of climate uncertainty
Probably a minor change manageable
Definitely a huge planetary change consider
living in space
6
Can we just adapt to climate change?
7
Adaptation is not free

• Cost of turning Bangladesh into the Netherlands?
• System of basic river dykes alone costing 16 of
  Bangladeshi GDP

8
Adaptation is not easy, especially when you dont
know what youre adapting to
?
??
9
Evidence suggests we are not perfectly adapted
even to todays climate, even in rich countries
10
How would you adapt to these things?

• Radical melting of the Greenland ice sheet
• Shutoff in the Atlantic thermohaline circulation
• Collapse of the West Antarctic Ice Sheet
• Changes in the severity and frequency of El Niño
• Indian monsoon chaotic multistability
• Dieback of the Amazon rainforest
• Etc.

11
We dont have one of these
Or rather we might its called reducing
greenhouse gas emissions
12
Reducing emissions another form of adaptation
13
We already have the technology to stabilise
greenhouse gases
14
And it wont cost the Earth
Actual price of a permit in the EU Emissions
Trading Scheme
15
Worth taking out the insurance? Most economists
think so

• Just as people spend a small slice of their
  incomes on buying insurance on the off-chance
  that their house might burn down, and nations use
  a slice of taxpayers money to pay for standing
  armies just in case a rival power might try to
  invade them, so the world should invest a small
  proportion of its resources in trying to avert
  the risk of boiling the planet. The costs are not
  huge. The dangers are. From The Economist,
  November 2006