Much of the discussion about cutting the carbon emissions that are slowly destroying our planet centers on the supposed cost of all these new forms of clean energy. A new report suggests: what costs?

Yes, changing over our planet's dominant power supply from one powered by fossil fuels to one powered by cleaner forms of energy will be enormously expensive. And yes, the tax on carbon emissions that it will likely take to spur companies towards clean energy will be enormously expensive, to polluters. But, as today's report from the Global Commission on the Economy and Climate points out, these costs are only part of the economic story of climate change. In order to get a full picture of the economic impact of various courses of action, we must also take into account the costs of not curbing our carbon emissions, as well as the potential economic benefits that clean energy investment could provide for us in the long run.

These sorts of long-term estimates on a global scale are inherently imprecise. (And in this case, one economist warns the New York Times, the estimates involve coming up with economic values for things like human lives saved, which can obviously vary.) That does not mean they are unimportant. In at least a general way, today's report estimates that the overall cost of doing the hard work to avoid the most extreme consequences of climate change might add up to something like... zero. From the report:

It is very difficult to estimate the economic costs of such effects, as there are many uncertainties. But the Intergovernmental Panel on Climate Change (IPCC) suggests that the likely costs of just 2°C of global warming would be of the order of 0.5–2% of global GDP by the middle of the century, even if strong adaptation measures are taken. Once warming has proceeded beyond this, the costs will rise further – though the IPCC finds there is too much uncertainty to estimate reliably by how much...

Even before accounting for climate action, the global economy will require substantial investments in infrastructure as the population and the middle class grow: an estimated US$89 trillion by 2030 across cities, land use and energy systems. For a good chance of keeping global warming below 2°C, a large share of those investments will have to be reallocated. Improving the energy-efficiency of buildings, industry and transport, for example, could require an additional US$8.8 trillion of incremental investment, as analysis for the Commission shows. Deploying low-carbon technologies including renewables, nuclear and carbon capture and storage (CCS) could require another US$4.7 trillion. Yet a low-carbon scenario could also save money in other areas, such as US$5.7 trillion saved in fossil-fuelled power plants and along the fossil fuel supply chain, and up to US$3.4 trillion from building more compact, connected cities and reducing sprawl.

Overall, the net incremental infrastructure investment needs from a low-carbon transition up to 2030 could be just US$4.1 trillion, if these investments are done well. In this case, the infrastructure capital needed for a low-carbon transition would be only 5% higher than in a business-as-usual scenario, helping to limit future climate impacts and adaptation costs. Other studies have suggested even lower investment needs, given some of the potential synergies in fuel and infrastructure savings.

In other words, the savings from smart investments in energy efficiency, mass transportation, clean fuels, and good urban planning could offset so much of the costs of this massive changeover that its final price was just barely higher than keeping on the same path that we're on now. And it would come with the added bonus of not consigning us to the worst kinds of climate change-fueled doom.

It's not financial gospel. It is, however, a good framework to use when someone starts talking about how curbing carbon emissions will be "too expensive."

Shout it in the streets.

[Photo: Getty]