The science behind the warming effect of CO2 has been well established for over 100 years. Indeed, without CO2 the earth would be about 30°C cooler than it is.
Global average temperatures have risen by approx 0.75°C. in the last 100 years. Over the last 50 years the amount of CO2 in the atmosphere has increased by approximately 25%. It is now 30% higher than at any time in the past 800k years.. (Explaining the Evidence of Climate Change, Prof. Julia Slingo, UK Met.Office website [metoffice.gov.uk] accessed 27th March 2010)
Those are the facts and, whilst some climate sceptics will claim the source quoted is discredited, these facts can be found on the websites of all the major nations’ meteorological services as well as university based climate research organisations.
And in July 2010 the latest "State of the Climate" report from the US National Oceanic and Atmospheric Administration (NOAA) confirmed that the trend is continuing.
How to Mitigate Harmful Effects
So we are where we are because of man-made global warming. And the trend will continue unless and until the amount of CO2 decreases. The important questions are “Does it matter? Are the consequences beneficial or harmful?” And, if the latter, can anything be done to mitigate the harmful effects that doesn’t produce even greater harm?
It is much harder to find authoritative answers to these questions. A Google search reveals numerous blogs and websites put up by special interest groups that refer to sometimes speculative and rarely authoritative predictions about potentially serious effects on food production, on health and on the frequency and severity of extreme weather events. It is much harder to find any reference to possible beneficial effects.
Perhaps the most authoritative source for information about the possible effects of warming on the world’s economies is the Stern Report. This is a report commissioned by the British Government and published in 2006. It evaluated the economic consequences of doing nothing and identified courses of action that might mitigate some of those consequences.
Benefits of Global Warming
In his executive summary Stern makes it clear that such predictions are not, and should not be taken as, precise. They depend on assumptions about the probability of certain outcomes. However, some of the broad conclusions of this work are worrying and will be dealt with below. First it is worth highlighting some of the benefits of global warming, at least for populations living in higher latitudes. These include:
- Higher agricultural yields
- Lower winter mortality
- Lower heating requirements
- A possible increase in tourism
However, the report goes on to say that these effects are likely to be offset by damage to infrastructure, bio-diversity and human health.
The greatest impact, according to Stern, will be felt by the poorest nations because of their location in areas subjected to the effects of rising sea levels or by drought.
Whilst predictions of the amount of increase in sea level caused by continuing global warming vary enormously, the reality for people inhabiting delta regions in the tropics, such as Bangladesh and Vietnam, is that a very small rise is all it takes to remove or poison large areas currently used for food production.
The Economics of Climate Change
Stern and his team put all these potential effects and their probabilities into computer models using a range of assumptions and concluded that the minimum cost of doing nothing is a reduction in world wide consumption of 5%. The worst case scenarios that were examined produced the worrying conclusion that world standards of living could fall by as much as 20%.
The mitigating actions proposed fall into 4 categories:
- Reducing demand for emission intensive products and services
- Increased efficiency which can reduce costs as well as emissions
- Action on emissions from non-energy sources such as deforestation
- Switching to lower carbon technologies for power, heat and transport
The principle assumption on which the team based their estimate of the cost of these actions was an aim to stabilise atmospheric CO2 at 500 to 550ppm by 2050. The cost of implementing the kinds of changes possible in each of these categories is estimated at 1% of world wide GDP with a range from an actual saving of 1% to a maximum cost of 5%.
Stern acknowledges that for some sectors the costs will be higher but the point is also made that there will be opportunities for growth generated by the transition to a low carbon economy. These include the development of low carbon technologies with a potential market worth $500bn by 2050. It is not surprising therefore that the report concludes that the cost of taking action is far less than the most likely cost of doing nothing.
This seems to contradict the sceptics’ charge that such costs represent an unacceptable tax on businesses and people. (Stern Review on the Economics of Climate Change, British Government Office of Climate Change. Executive Summary Accessed on World Bank website March 27th 2010)
Frank Parker - Frank writes regularly on a diverse range of subjects which he researches thoroughly.
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