Climate negotiators meeting in Dubai last month pledged to chart a course for stabilizing the climate system using good science. But many scientists say these promises are at best ill-defined and at worst a travesty of good science — vague and full of loopholes.

The U.N. climate conference in Dubai agreed on an action plan for two key objectives: to keep the world on track to limit global warming to 1.5 degrees C (2.7 degrees F), and to stay below this threshold by achieving net-zero greenhouse gas emissions by 2050. Negotiators pledged that both objectives would be pursued “in keeping with the science.”

But neither of the objectives have agreed definitions that would allow a judgment on whether they have been achieved. Two studies published during the Dubai event exposed the problem and revealed wide gaps opening over both the 1.5-degree and net-zero targets, exposing the tensions between political expediency and scientific probity.

On the 1.5-degree target, British meteorologists reported in the journal Nature that a lack of agreement on how to measure global average temperatures is likely to delay formal recognition that the […]