From ARS Technica

There are a lot of ideas on how to limit emissions of CO2 in order to avoid the worst impacts of climate change and ocean acidification. But most of those focus on future infrastructure and equipment; in the meantime, we have a large portfolio of power plants and vehicles that will continue to emit for as long as we use them, and we're unlikely to stop doing so. Just how significant are the carbon emissions that we've committed to? A study that will be released by Science today indicates that we're not in terrible shape yet, as we haven't built the hardware that could cause the most significant shifts in the climate.

The new analysis focuses on what it terms "committed emissions" by taking known values like a car's typical emissions per year of driving, and totaling those for the projected lifespan of the vehicle. The database the authors use for this has separate figures for passenger and industrial vehicles, and provides numbers for things like coal-fired power plants and the like. For land use changes, it relies on values in the IPCC report. It also has figures for fossil fuel use by industrial equipment and the like, but these are simply based on total energy consumption, as this hardware is too varied to project accurately.

There are a couple of additional limitations to the work. For example, they leave out the impact that building infrastructure, like a highway system or electric grid, has on emissions. In addition, they recognize that any effort to actually stop building further fossil fueled hardware is likely to extend the lifespan of the stuff that already exists. For these reasons, the authors caution that their "scenarios are not realistic."

Nevertheless, they suggest that the results could be valuable, as they will provide some guidance about when certain steps would have to be taken to meet targets for future emissions. Should the growth of fossil fuel use continue, they'd also provide a hint of when we might have to get serious about alternate approaches, like geoengineering and carbon capture and storage.

[More...] [Comments...]