If global energy policies lead to stabilisation of CO2 concentrations at 660 p.p.m., what would the resulting increase in GMST be (to one decimal place)? In subsequent parts of the question this is referred to as the UN’s ‘de facto temperature target’
To determine the resulting increase in Global Mean Surface Temperature (GMST) if global energy policies stabilize CO2 concentrations at 660 p.p.m., you would need to consider various factors and processes involved in climate change. Here's a step-by-step explanation of how you can approach this question:
1. Understand CO2 Concentration and GMST: CO2 concentration refers to the amount of carbon dioxide present in the Earth's atmosphere, often measured in parts per million (p.p.m.). GMST is a measure of the average temperature of the Earth's surface.
2. Recognize the relationship between CO2 Concentration and Temperature: CO2 concentration is a major driver of global warming. As CO2 levels increase, it can lead to higher temperatures, known as global warming or climate change.
3. Research Climate Sensitivity: Climate sensitivity refers to how much the Earth's temperature will increase in response to a given increase in CO2 concentration. It is typically expressed as the increase in GMST per doubling of atmospheric CO2 levels.
4. Determine the Climate Sensitivity Value: Different climate models provide various estimates of climate sensitivity. The Intergovernmental Panel on Climate Change (IPCC) estimates a range of climate sensitivities, but for this explanation, let's assume a value of 3.0 degrees Celsius (°C) per doubling of CO2.
5. Calculate the GMST Increase: To calculate the GMST increase, we need to determine the difference between the CO2 concentration stabilization level of 660 p.p.m. and the concentration level at the pre-industrial era, usually around 280 p.p.m.
a. Calculate the number of doublings: To find out how many doublings from the pre-industrial level to the target level, divide the target concentration by the pre-industrial concentration:
Number of doublings = log2(660/280)
b. Calculate the GMST increase:
GMST increase = Climate Sensitivity * Number of doublings
For the given climate sensitivity of 3.0°C and the number of doublings calculated in step 5a, you can then determine the GMST increase.
6. Round to One Decimal Place: Finally, round the calculated GMST increase to one decimal place, as mentioned in the question.
Remember that this is a simplified explanation of the process of estimating the resulting increase in GMST. In reality, climate projections involve numerous complexities and uncertainties, including feedback mechanisms and other greenhouse gases. Actual climate models and scenario analysis can provide more accurate and comprehensive estimations of future GMST increases.