Read the article. It doesn't say we should be complacent, but it does caution about panicking over "catastrophic" climate-change from methane. As for our needs in cutting carbon-emissions, well not to worry. Peak Oil will soon take care of emissions from tractors, trucks, ships, cars, airplanes and processing plants. It's going to be ugly and violent for a lot of people though (if education doesn't get out about permaculture). Natural gas is strongly correllated to oil-production and that will be greatly reduced very soon too (hence the recent talks by BP over shale-gas, which is highly controversial). Future economic contraction is inevitable. Its going to happen naturally - and will be quite brutal sadly.