Ed: Woods Seminar: Pacala - Equitable Solutions

Posted by: Max Dunn on November 6, 2008 09:50:37

It was exciting to hear from Stephen Pacala of the Pacala/Socolow CO2 reduction "wedges" plan. Usually he gives an optimistic message but today he is going to tell us what he really thinks which will temper his usual optimism.

Equitable Solutions to the Carbon and Climate Problem

Stephen W. Pacala
Petrie Professor of Ecology
Director Princeton Environment Institute

Today will tell use what he really thinks, which will temper his usual message of optimism

• Four forbidden phrases
  1. There is no climate change problem
  2. We lack the technology to solve it
  3. The solution would be too expensive
  4. We can’t solve it because the big emitters won’t play fair

Climate problem

• There is no definite scientific proof that CO2 won’t change the climate
• But there is a lot of uncertainity

• Many people felt that 2x CO2 would be a success
• “Monsters Behind the Door” Ice sheets, ocean circulation, hurricanes, Sahel Drought
• If we burn all our fossil fuels, CO2 will be 7 times greater
• To reach 500 PPM for the next 50 years, would need radical decarbonization of rich companies
• To limit warming to 2% C, would need radical decarbonization of both rich and poor countries
• When we talk about a lower target, we are talking about what the poor countries need to do
• Lieberman/Warner calls for almost complete decarbonization by 2050

Carbon Cycle

• 818 billion tons of CO2 in the atmosphere
• Every year 8 billion tons go into the atmosphere
• Oceans absorb 2 billion, land absorbs 2 billion
• So 4 billion net tons of CO2 added to atmosphere
• For 30 years, emissions increased at 1.5% per year, but recently increased to more 3%
• If rate is 3% per year, wedges won’t be enough
• Expects that the increase is actually about 2%
• Oceanic sink was expected to increase in strength, but recently has been storing less. This was due to change in winds, which could be a result of climate change

Land Sink

• Behaving unexpectedly, most worrisome
• Models predict a big sink from CO2 fertilization
• TAR predicted 6 billion tons of sink per year in 2050
• LM3V modeled running completely dynamically suggests that climate will stabilize at today’s temperature
• Ran again to see how it would come to equilization with no CO2 fertilization
• Without CO2 fertilization biosphere loses 444Pg and gains 1.4 deg C because warming will cause loss of forests in Amazon and Arctic
• Norby et all 2006 showed that CO2 fertilization linearly increases CO2 sink of young trees
• Korner et all 2006 look at mature forests in Switzerland and found no increase in sequestration with increasing CO2
• IPCC models assumed that other things plant needed would be available, in particular nitrogen and phosphorous
• However nutrient limitations may prevent plants from capitalizing on the CO2 fertilization
• But some plants can fix nitrogen, which may provide enough
• If plants don’t have CO2 fertilization, it would require an additional 26 wedges to offset
• US Forest inventory shows static of declining forests
• They looked at growth rate of plants and concluded that plants were not growing faster now that there is more CO2
• Looking at longer data, is also seeing growth slowing
• In tropics, a study showed a jump of 20x greater growth than expected by CO2 fertilization, so another mechanism was probably at play
• Total northern landuse sink is about 1 B ton CO@
• Amazon has very little secondary forest,
• Cropland and pasture hasn’t increased as much over the last 30 years, but secondary forests has increased a lot
• Secondary forest sink in tropics is about 0.6 B ton Co2

Solution Would Be Too Expensive

• Models say would take 1% of GDP in 50 years
• But in the marketplace today if $100/ton carbon would lead to 25 cents gas, 1.2 cents electricity, $12 per barrel of crude, $100 million total economy

Big Emitters

• Non OECD countries no emit more than OECD countries
• Fairness
  • Poor countries say it isn’t fair for them to pay for problems that the rich countries created
  • Rich countries say that they can’t reach a solution without participation of poor countries
• Two ways to calculate individual emissions:
  • Bottom up – look at what people use: as income goes up, emissions go up less (a * personal income ^ b) where b is about 0.8
  • Top-down: look at distribution of incomes and total emissions
• Top down shows:
  • The richest 500 million people emit half the worlds carbon. Make 100k Euros per year
  • The bottom half emits almost nothing

• What number would you have to set a personal emissions limit to limit CO2 at 500 PPM?
• No-one that earns less than $40k would be affected
• Could also limit by country.
• The US is currently the most unfair, but would pass under Lieberman/Warner
• Under this, China would have to decrease as much as the US
• India wouldn’t have to cut it emissions until 2030

Q and A

• We have to adapt no matter what, the question is how much adaptation and how much prevention do we attempt?