Stockholm, Dec 8 (IANS): American economist and 2018 Nobel laureate William Nordhaus said on Saturday that participation in climate agreements needs to be mandatory for all countries.

Nordhaus, a 77-year-old economics professor at Yale University, was awarded this year's Nobel Prize in Economic Sciences for inventing macroeconomic analysis models that take into consideration the effects caused by climate change and the corrective policies that can be used to counter its damage.

In an interview to Efe news, Nordhaus criticized previous climate agreements such as the yearly UN Climate Change Conferences, the Kyoto Protocol, the Copenhagen Agreement and the Paris Agreement.

The American economist said none of them had imposed any kind of responsibility and instead were completely voluntary, which he described as the main reason they had made no effect.

Nordhaus said that, in his view, countries should have certain obligations, responsibilities and commitments in order to obtain results from a climate deal.

Nordhaus said this obligation had to "go beyond being mandatory" by also imposing punitive sanctions on the countries refusing to participate in an agreement.

He added that he was keeping an eye on the ongoing Katowice climate change conference (COP24), in which key aspects of the Paris Climate Agreement were set to be implemented.

Nordhaus is currently in the Swedish capital, Stockholm, where he will receive the Nobel Prize alongside fellow American economist Paul Romer at an official ceremony on Monday.