Even if all these problems were overcome and every nation lived up to its commitments, the effect on the planet would be negligible. Bjorn Lomborg, head of the Copenhagen Consensus Center, did the math in a new study published in the journal Global Policy. “If all nations keep all their promises, temperatures will be cut by just 0.05°C (0.09°F),” he stated in the news release. “Even if every government on the planet not only keeps every Paris promise, reduces all emissions by 2030, and shifts no emissions to other countries, but also keeps these emission reductions throughout the rest of the century, temperatures will be reduced by just 0.17°C (0.3°F) by the year 2100.”