The global discussion about cutting carbon emissions often centers on how much it would cost in the short term. But in the long term, trillions of dollars could be saved.

Yes, it will cost money to upgrade our buildings and transportation systems and energy systems in order to cut back on carbon emissions. And since most politicians are very geared towards short-term savings, such upgrades seem daunting. The alternative, however, is much greater cost down the road from disastrous results of climate change. And, on an even more mundane level that may appeal to budget nerds, carbon inefficiency across the world costs us tons of money each year even without apocalypse.

A new report from a multinational commission of climate experts finds that a concerted carbon-efficiency effort from just the world’s cities could save close to $17 trillion over the next 35 years. The necessary steps include compact city planning, more efficient building codes, better transportation efficiency, and upgraded city recycling plans. A brief cost-benefit analysis, from the report:

Even with this focus on the low-carbon options that could be adopted or promoted by local government, and with conservativeand time-limited estimates of costs and benefits, the analysis finds a compelling economic case for significant low-carboninvestment in cities. In the “medium” scenario, the gross global costs of these investments would be US$977 billion per year in2015–2050 (equivalent to 1.3% of global GDP in 2014), but they would reduce annual energy expenditure by US$1.58 trillionin 2030 and US$5.85 trillion in 2050...While we must acknowledge potentially significantopportunity costs, this means the low-carbon investments collectively would pay for themselves within 16 years. The currentvalue of the stream of net savings they would generate for cities in 2015–2050 (measured as a net present value or NPV) wouldbe US$16.6 trillion.

Seems like a good investment.

Also we need a carbon tax.

[The full report. Pic via AP]