CIEL - Climate Impact Equity Lens | Climate Change Gets Personal

What is CIEL?

CIEL personalizes the consequences of global warming by showcasing the costs of climate damages and emissions reductions on an individual level. It estimates and compares the individual costs and the individual benefits of climate change. To do this, CIEL imagines two possible futures: one is a world in which nothing is done to combat climate change; the other is a world where maximum efforts are made to reduce emissions.

In the do-nothing future, the failure to reduce greenhouse gas emissions has a negative consequence and a (less obvious) positive consequence: higher temperatures, more acidic oceans, and changes to historical weather pattern cause damages around the world; but by failing to pay for emission reductions, we all save money. CIEL compares each individual's damage costs to her savings from not reducing emissions to find out whether, in a given year, she is a net winner or a net loser from climate change.

The Bad News: Climate Damages

Hotter temperatures, higher sea levels, and a departure from historical weather patterns result in costly economic damages to many people around the world. By 2100, temperatures are nearly 4°C higher than they were in pre-industrial times, and climate damages are swallowing up about one-sixth of global economic output, and a much greater share of national income in some countries. In this "business-as-usual" world, temperature increases top 7°C by 2200, when three-fourths of all global output is lost to climate damage.

There is a lot of great information online documenting the latest scientific knowledge about the effects of climate change. We won't try to repeat that here. In CIEL, each person's damages are the economic losses from climate change that could be prevented by reducing greenhouse gas emissions – or the difference between that person's business-as-usual damages from a high-emissions scenario and their (relatively small, no longer avoidable) damages from a very-low-emissions scenario.

The Good News: Savings from not Reducing Emissions

On the bright side, not acting to reduce emissions and prevent dangerous climate change could save most people a lot of money right now. Look at it this way: Cutting down on emissions, in a future where we take climate policy seriously, will mean higher energy and transportation costs for just about everyone. Not lowering emissions means that, in comparison, you save money. The money not spent is the savings from failing to reduce emissions.

CIEL assumes that, if efforts were made to reduce emissions, each person would have to pay her own share of emission reduction costs. (Rich countries would not, for example, contribute funding for emissions cuts in poor countries, and rich people would not subsidize emissions cuts by the poor within their own countries.) Given this assumption, reducing emissions would mean that most people around the world would have to pay higher energy and transportation costs. But if we don't reduce emissions, then everyone "saves" by avoiding those cost increases.

Savings from Climate Change?

This effect may be somewhat counter-intuitive to many CIEL users at first, but consider this: Emissions reductions require investment in new infrastructure and technology, mostly in the energy and transportation sectors. This investment has two effects: 1) it strengthens the economy (and hopefully makes everyone's income a little bit higher); and 2) it increases consumer prices for energy, transportation, and goods that require a lot of fossil fuels to produce.

CIEL uses emissions reduction cost estimates from the very-low-emissions CRED scenario in which everything that can be done to reduce emissions is done. In this scenario, emissions cuts have a different price in each world region. Investment in lowering emissions does increase incomes, but it also increases the costs paid by consumers. Each person's savings from not lowering emissions in CIEL are the value of those potential higher costs (if emissions cuts were made) as a share of her new, slightly higher income.

Why Is There No International Aid in CIEL?

The CRED model – on which CIEL bases its temperatures, damages, emissions reduction costs, and incomes – is unique among climate-economics models in its ability to explicitly model the effect of allowing or prohibiting international aid. CIEL uses CRED model results that assume there would be no international aid – both in the high emissions and very-low-emissions scenarios. This "no aid" assumption demonstrates the full impact that climate change would have on low-income countries in the event that high-income countries fail to provide economic assistance for low-carbon development in their poorer neighbors, and fail to live up to the promise of "common but differentiated responsibilities."

If, instead, CIEL were to include international aid for emissions cuts, the effect would most likely be to make success in reducing greenhouse gas emissions look like an even better deal for people in poorer countries (as compared to the actual CIEL scenarios, which do not include international aid) and a somewhat worse deal for people in richer countries.

The CIEL Graph

CIEL compares each person's damages from the failure to stop climate change to her savings from not paying for emissions reductions. On the CIEL graph, shown here for three sample individuals in 2100, both damages and savings are shown as a share of each person's income. That's because $500 (in U.S dollars) in losses or gains is worth a lot more to someone who makes $5,000 a year than it is to someone who makes $50,000 a year.

Each person is represented as a letter marked on a graph. If a person's marker is above and to the left of the red break-even line, she suffers net losses from climate change (her climate damages are larger than her savings from not reducing emissions in a given year). If her marker is below and to the right of the red line, she benefits from net gains (her damages are smaller than her savings).

Who are A, B, and C in this example? We look at them next.