Copenhagen consensus: Technology, geoengineering, and low carbon taxes are favored solutions for tackling global warming.

There’s No One Perfect Fix for Climate Change

There’s No One Perfect Fix for Climate Change

The 10 most effective ideas for improving the world.
May 9 2012 2:52 PM

There’s No One Perfect Fix for Climate Change

Slate readers debate their favored solutions for the world’s biggest problems.

The idea behind Copenhagen Consensus 2012 is to prioritize some of the world’s most important spending, with the latest economic analysis providing us with an input. In a series of articles, I am drawing on new research papers that present the costs and benefits of the smartest ways to respond to global challenges. Each article has a poll, and Slate readers can vote on the investments that they believe should be the highest priorities—along with those that should not. You can read more about the rationale behind the project here.

Over the course of the series, we will see how readers rank responses to a range of challenges, and at the end we will identify the investments that Slate readers think should be the highest priority. We will be able to contrast these with the findings of a panel of Nobel laureate economists.

We heard from someone who questioned the science behind climate change. My perspective is pretty simple: Global warming is real, it is caused by man-made CO2 emissions, and we need to do something about it. But we don't need action that makes us feel good. We need action that actually does good.


That’s why it’s so interesting to be able to compare the four different approaches, like we did yesterday. We have different policy levers: what can we achieve with them?

One reader pointed out that geoengineering would fail to halt ocean acidification. (I’ll draw here from the chapter on geoengineering in the book Smart Solutions to Climate Change, written by the same authors as this geo-engineering paper). The ocean becomes more acidic as it absorbs CO2 from the atmosphere. Over time, studies suggest this could disrupt marine ecosystems. Acidification and warming are likely to interact: Acidification, for example, weakens the ability of coral reefs to recover from bouts of bleaching caused by warm ocean temperatures and might also harm other species near the base of the ocean food chain. The severity of the problem is poorly understood but is causing concern.

It’s correct that the geoengineering proposals mooted wouldn’t halt ocean acidification. There could be other, more novel approaches that might. But it’s relevant to keep in mind that some analysis suggests that there is no solution currently on the table that would actually tackle all of the problems and effects of climate change. Even very severe controls on carbon emissions might fail to halt the destruction of many coral reefs: We don’t know the effects of the carbon that has already been emitted. And certainly, any politically realistic and feasible carbon restrictions will not completely stop global warming, meaning some damage will still occur.

Other readers talked about the discount rates that the Copenhagen Consensus 2012 authors used. The Copenhagen Consensus Center asked all authors to use two discount rates: 3 percent (low) and 5 percent (high). I would note that most developing countries would use much higher discount rates.

Now, let’s turn to your latest rankings.

1 Family Planning Population Growth
2 Bundled Micro-Nutrient Interventions Hunger and Malnutrition
3 Tobacco Taxation Chronic Diseases
4 Effective Early Warning Systems Natural Disasters
5 Expanded Childhood Immunization Coverage Infectious Disease
6 The Reinvented Toilet Water and Sanitation
7 Agricultural Productivity R and D Biodiversity
8 Increased Funding for Energy R and D Climate Change
9 Subsidy for Malaria Combination Treatment Infectious Disease
10 Hepatitis B Immunization Chronic Diseases
11 R&D to Increase Yield Enhancements Hunger and Malnutrition
12 Deworming of Children Infectious Disease
13 Extension of Protected areas Biodiversity
14 Geo-Engineering R&D Climate Change
15 Protecting All Forests Biodiversity
16 Community Led Total Sanitation Water and Sanitation
17 Expanding Tuberculosis Treatment Infectious Disease
18 Adaptation Planning Climate Change
19 Acute Heart Attack Low-Cost Drugs Chronic Diseases
20 Retrofitting Schools to Withstand Earthquake Damage Natural Disasters
21 Generic Pill for Heart Attack Risk Reduction Chronic Diseases
22 Low$1.8/tC Global Carbon Tax Climate Change
23 Investing in Accelerated HIV Vaccine Development Infectious Disease
24 Sanitation as a Business Water and Sanitation
25 Strengthening Structures Against Hurricanes and Storms Natural Disasters
26 Community Walls Against Floods Natural Disasters
27 Increase Competition in the Fertilizer Market Hunger and Malnutrition
28 Salt Reduction Campaign Chronic Diseases
29 Crop Advisory Text Messages Hunger and Malnutrition
30 High $250/tC Global Carbon Tax Climate Change

Remember: You can still go back and vote in all of the various polls today, and you can vote today on options to respond to armed conflict; we’ll be finalizing the Slate readers’ list at the end of the series. If you disagree with this ranking, vote!

We can see that the technology-led response to climate change (involving increased funding for energy R&D) is the top-ranked climate solution, and is in a very respectable eighth place among all of the priorities that readers have looked at so far. Geo-engineering gets a fair ranking, and so does adaptation investment. A low carbon tax fared slightly worse, while the high carbon tax has been completely rejected by readers.