Yesterday, the International Energy Agency (IEA) released a report in which it urges the adoption of four approaches to curb greenhouse gas emissions by 2020. In announcing the report the IEA noted that, at the earliest, the next international treaty won't even be finalized before 2015 (and its implementation won't start until 2020). But in the intervening years, we're likely to build infrastructure and continue emissions that will make the goals of that agreement nearly impossible to reach. In the interim, the IEA suggests steps that are needed to keep the planet on a path that would limit emissions to 2°C.

The report comes immediately in the wake of the first recordings of carbon dioxide levels that exceed 400 parts per million at Mauna Loa, far from any sites of industrial emissions. These levels haven't been seen in millions of years and, if current emissions trends continue, we're expected to reach temperatures we've not seen in equally long: between 3.6°C and 5.3°C warmer than the preindustrial era, according to the IEA. And, as the World Bank recently noted, that sort of rise would radically reshape our world. So the IEA is sold on the goal of limiting future temperature rises to 2°C.

Unfortunately, energy-related emissions went up by 1.4 percent last year to 31.6 Gigatons. If we wait to 2015 to finalize plans to keep future temperature rises to 2°C, the IEA estimates we'll need to spend $5 trillion to get back on track.

In contrast, the IEA estimates that we can stay on track by spending $1.5 trillion in the years between now and 2020. If spent according to the IEA's new four-step plan, we'll save just as much money as we spend due to more efficient use of energy. The IEA focused on technologies that are already on the market and are in active use in some countries, meaning that there are no barriers other than cost and scaling.

The plan

One of the steps is something the IEA has been arguing for a while: given that there is a finite supply of fossil fuels and that burning them creates problems, it makes no sense to actively encourage their use. Despite this, fossil fuel is heavily subsidized in many countries. The IEA has consistently called for these subsidies to be phased out; one of its four points is to simply accelerate the phasing out.

While also on the subject of waste, the IEA would like to see oil and gas producers do more to capture methane that is currently allowed to escape into the atmosphere. Methane is a potent greenhouse gas and is eventually converted to CO 2 in the atmosphere; capturing more of it will account for 18 percent of the savings.

In the US, the expansion of renewables and natural gas has led to a significant decline in the use of coal, which has led to a corresponding drop in carbon emissions (coal is the least efficient fossil fuel in terms of energy per emissions); China's emissions growth is slowing for similar reasons. The IEA would like to see that happen globally. If we limit the construction and use of the least efficient coal plants for the rest of the decade, it could account for 20 percent of the IEA's goals.

But the biggest step we can take is simple efficiency. Building or retrofitting more efficient buildings, industry, and transportation could account for nearly half the emission changes needed for the IEA's plan. And this is where most of the money for the plan comes from; efficiency measures can usually save a significant amount on energy expenses, often with time windows of less than a decade. These savings are required to offset the cost of mothballing some of the coal plants before the end of their expected lifespans.

These savings will, of course, exact a cost somewhere, primarily in the energy industries. If the IEA's plan were adopted, coal consumption would obviously drop and some fossil fuel reserves that are currently slated for development will not be needed as quickly as expected. As a bit of a sop to the energy industry, the IEA notes that the problems caused by climate change—water shortages, severe storms, sea level rise—will exact a cost on the industry's infrastructure as well.

Overall, the IEA's plan seems like a solid one. But the group has been calling for many of these steps for a number of years and responses have been slow. There's definitely an element of the "tragedy of the commons" here. Although it's appealing in general to think that these efficiency measures could allow finite reserves of fossil fuels to last decades longer than they would otherwise, the countries and companies relying on the income from developing them are unlikely to be happy to go along with the plan.