Part 4 of 4: Green Technologies

This is the fourth installment of a four-part series published each Wednesday on Action Needed to Stop Global Warming.

1. How Warm is Too Warm?
2. Worldwide Emissions Target
3. U.S. Emissions Target
4. Technologies to Get Us There

In Part 1 of this series, I defined the global tipping point as the melting of the Greenland ice sheet, which could cause sea levels to rise 20 feet. In Part 2, I showed that to avoid this tipping point, global emissions of carbon dioxide (CO₂) must start to decline around 2020. In Part 3, I showed what the U.S. must do to help the world meet these targets.Meeting these targets will require significant changes in how we produce and use energy, and this makes many people nervous. They worry that the cost will wreck the economy, and they’ll have to give up their cars and air conditioning. Not true!

Studies show that the cost of taking action is much lower than the cost of inaction. The Stern Review on Economics of Climate Change examined this issue in depth. From the short version of the executive summary [PDF]:

Using the results from formal economic models, the Review estimates that if we don’t act, the overall costs and risks of climate change will be equivalent to losing at least 5% of global GDP each year, now and forever…

In contrast, the costs of action – reducing greenhouse gas emissions to avoid the worst impacts of climate change – can be limited to around 1% of global GDP each year.

Other studies confirm that the cost of reducing emissions will be around 1 percent of GDP. A study by McKinsey [PDF] found that the annual worldwide cost of reducing emissions would be 0.6 to 1.4 percent of GDP in 2030, and goes on to say:

If, as some participants in the climate debate argue, the cost of reducing emissions could be an insurance policy against the potentially severe consequences of unchecked emissions in the future, it might be relevant to compare the costs with the global insurance industry’s turnover (excluding life insurance) – some 3.3 percent of global GDP in 2005.

One reason costs will be lower than people fear is that we already have what we need. The technologies necessary to control CO₂ emissions for the next 50 years are available today. In a seminal paper in the journal Science (see summary [PDF]), Stephen Pacala and Robert Socolow showed that the problem can be addressed with at least 15 existing technologies and policy options (called “wedges”). None require us to give up our household amenities.

The wedges include energy efficiency and conservation, wind and solar energy, biofuels, carbon sequestration in soils and forests (with potential profits for farmers), clean coal technology, and – if problems such as waste disposal can be resolved – nuclear power. Although no single wedge can get us to where we need to be, any combination of about seven of today’s technologies can.

To prevent global warming from reaching the tipping point, we must lower CO₂ emissions as soon as possible. The technologies are already in hand to get started.

Tune in next week when I will begin a new series of posts focusing on some of the underreported consequences of climate change.