Transcript Document
Global Climate Change Understanding the MIT study & what it means for public policy MIT Study: 1- The Input Data Emissions, inflow, (billions of tons/year) 7 Anthropogenic CO2 Emissions 6 5 3 4 Emissions 3 2 1 net Removal, outflow, = 3 0 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 Edward J. Garrity 2000 2 MIT Study – 2, Hypothetical Future Atmospheric CO2 Gradually Rises to 400ppm & Stabilizes Anthropogenic CO2 Atmospheric level 440 420 400 380 360 CO2 340 320 300 280 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010 2020 2030 2040 2050 2060 2070 2080 2090 2100 Step 3 – Subjects asked to sketch the likely future CO2 emissions given this scenario above. Edward J. Garrity 3 MIT Study – 3, Example Results Emissions (inflow), Removal (Outflow) 9 Anthropogenic CO2 Emissions 8 7 6 5 Emissions 4 Net Removal 3 2 1 0 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010 2020 2030 2040 2050 2060 2070 2080 2090 2100 Edward J. Garrity 4 Edward J. Garrity 5 Why would smart people make this mistake? • Cognitive processing • System 1: Our brains operate automatically, quickly, little effort, involuntary reaction, intuitive, infers & invents causes & intentions, neglects ambiguity & suppresses doubt, is biased to believe & confirm, frames decisions narrowly • System 2: deliberate, effortful, rational Edward J. Garrity 6 System 1 at work • We tend to use the information that is readily available (WYSIATI) • System 1 is designed to jump to conclusions from little evidence; we construct stories from the evidence • IF the story has coherence, then we have confidence in our opinions Edward J. Garrity 7 MIT Experiment, CO2 levels • Problem was framed, presented in a simple manner: Atmospheric concentrations, what would future emissions look like? • System 1 at work: Two variables are related, correlation heuristic • If atmospheric CO2 levels off, then emissions must level off to match results • We easily ignore missing information Edward J. Garrity 8 Mental Model is Missing • Bathtub analogy for stock & flow dynamics Emissions, inflow Atmospheric CO2 Edward J. Garrity removal, outflow 9 Stock & Flow Reasoning • In order for Atmospheric CO2 levels to level off (equilibrium), … implies that inflows = outflows • In 2000, inflow from human activity is 6 bil. Tons, but outflow (removal) is 3 bil. tons • By 2080, inflow (from industrial activity) would need to be reduced to 3 bil. tons • Therefore, need to decrease by 50%! Edward J. Garrity 10 Implications • Public does not understand the problem • More needs to be done to halt Global Climate Change than people realize • Although it is extremely difficult* to get, for example, a 20% decline in use of fossil fuels, … simply reducing by 20% means that we are still losing ground (Earth is heating). We need to get at least 50% reduction to keep stable Edward J. Garrity 11