People argue about whether or not, or how much carbon emissions should be taxed or limited. Often one side says that climate change will have disastrous effects, killing millions or even billions of people, submerging whole island countries because of a melted Arctic and Antarctic ice sheets, weather that makes it very difficult to grow food, and that this is the scientific consensus that 97% of scientists agree with. The other side often claims that climate change is caused mostly by factors such as solar cycles, therefore people can’t change the climate much by reducing carbon dioxide emissions, or they claim that the positive effects of climate change outweigh the negatives.

What is the scientific consensus on climate change? And most importantly what should be done about it?

The “97% percent consensus,” figure comes from a study showing that of over 4 000 abstracts on climate change in the scientific literature expressed the opinion that humans are causing global warming.¹ This done not mean that major action is necessary on climate change, if any. But news organizations and people, including the President Obama, misinterpreted the claim, saying that climate change is, “dangerous”.^Q1

A more comprehensive study showed that less than 7% of climate scientists think that the upper limit of sea level rise is more than 2.5 metres by 2100, and 53% of climate scientists think that a sea level rise of 0.35 metres is the lower limit 2100. Only 30% of climate scientists are 90% or more sure that the earth was warmer the past decade than in medieval times.⁸

But more important is what should be done about climate change. 73% of human caused greenhouse gas emissions are caused by electricity, mostly from coal power.² For every 1.6 kwh produced, there is an average of $US 1 in productivity supported.³ This means that it is better to produce power than not if the cost is less than $US 0.62 per kWh^E1 for the average use(at purchasing power parity). Most coal power plants produce less than 0.001 tonnes of CO2 per kWh.⁵ The estimate from the EPA on the cost of putting one tonne of carbon dioxide in the atmosphere(including things like health and ecosystem damage, not just the change economic productivity) is $US 36.⁴ This brings the price of coal power from $US 0.08 per kWh to $US 0.116 per kWh, which is sometimes less and sometimes more than low polluting electricity sources.⁶

If the case can be made that it would be better for a renewable source of electricity to be built instead of a coal power plant in a specific scenario, it should be done, however $US 0.116 per kWh is not enough to make it a good idea in most cases. In some areas there isn't enough sun for solar plants, not enough wind for wind turbines, no rivers for hydroelectric power, and not enough demand or capital for nuclear power which costs a lot of money to build. It is especially true in poor countries. If there are 1 million people in a country living in extreme poverty at $US 550 per year and a coal plant is built that produces 500 MW, that builds up the industry in the area that creates $US 0.62 of productivity per kWh used, and the cost of electricity is $0.116 per kWh including the environmental cost, $US 2 200^E2 will be added to the economy per person per year. This 5 times increase in GDP will result in a 9.7 year^E3 increase in lifespan of the people.⁷ This means that such a coal plant will save 9 700 000 years of life for the people currently living there, because of its benefits to the economy. This 9.7 year increase in lifespan is dependant on GDP(PPP) not income, so even though the wealth is not spread evenly, it still results in the lifespan increase because of higher wages. If there is a river in the area that could get a hydroelectric dam built with a lower cost of electricity, it should be done instead. But sometimes there is no access to renewable power, so coal power is the best way to go.

Equations:

E1. 1.62^(-1)

E2. (500000*8760*(0.62-0.116))/1000000

(kW*hours per year*(value added per kWh - cost per kWh))/number of people

E3. ln(5)*6.0406

[From source 7]

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