About this site
Net Zero Cost Benefit compares the benefits and the costs of net zero climate policy: going net zero by 2050, for any country or group of countries. The benefits are a cooler world and lower climate damage for everyone; the cost is slower growth for the country or countries that act.
Temperature
How much cooler would the world be if part of the world went net zero by 2050? The site compares two futures: one where everyone keeps today's policies, and one where any country or group of countries goes net zero. A climate model used for the UN Climate Panel's reports since 1995, MAGICC, turns both into temperatures. The difference is the effect of net zero.
Costs
The cost comes from integrated assessment models, the climate-economy models the UN Climate Panel uses to estimate what climate policy costs. For world net zero by 2050, the site uses AIM's estimate: 7.8% of world GDP in 2050, or 7.2% measured from current policies.
The estimate draws on several lines of evidence. The UN Climate Panel and later studies have collected nearly 1,000 scenarios from these models. Split by modeling team and extended to a full net-zero cut, they give a cost of global net zero by 2050 of about 4% to 13% of world GDP in 2050. Only six scenarios actually reach, or nearly reach, net zero by 2050, and three of them are out of date: they assume deep emission cuts that should already have happened before 2025. Of the three left, which cost from 3% to 19% of GDP, AIM's (EN_INDCi2030_500f; Riahi et al. 2021) is the middle one, and below both the median (9.8%) and the average (9.4%) of the modeling teams.
Benefits
The benefit is the climate damage avoided by lower temperatures. It uses the average of two summaries of the studies of climate damages: one by Richard Tol, one of the world's most cited climate economists, and one by William Nordhaus, the only climate economist to win the Nobel Prize in economics.
Who made this
This website was created and designed by Dr. Bjorn Lomborg, who also carried out the analysis. Dr. Lomborg is President of the Copenhagen Consensus Center and Visiting Fellow at Stanford University's Hoover Institution. The AI assistants Claude and ChatGPT helped with data processing and coding.
Bio · lomborg.com · Hoover Institution
Free to share
All the cards and videos on this site are free to share and republish, unaltered. They already carry the NetZeroCostBenefit.com credit. Formally, they are released under the Creative Commons Attribution-NoDerivatives 4.0 license (CC BY-ND 4.0).
How the numbers are shown
The two temperatures shown together have the same number of decimals as their difference (at least two): in the chart to 2100, the difference in the headline; in the year table, the difference in the selected year. So that they add up, the net-zero temperature is shown as the rounded current-policy temperature minus the rounded difference; this moves it by at most one unit in its last decimal. Shares of emissions are shown with two significant digits, and money amounts in the headline and tables with three; the labels on the annual chart are rounded more compactly.
Privacy
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Download the data
Every number on this site can be checked. The download has the results for every country and group, with the code that recomputes them, and the data behind every chart and background analysis, scenario by scenario, together with where to get every dataset and model the site uses.