Following commitments to cut emissions of greenhouse gases from two of the world’s top polluters -- China and the United States -- leaders from over 190 countries have gathered in Lima, Peru, for the twentieth session of the United Nations Climate Change Conference, scheduled to begin Monday. The summit will aim to hammer out a new international climate change deal ahead of key talks in Paris next year.

“Never before have the risks of climate change been so obvious and the impacts so visible. Never before have we seen such a desire at all levels of society to take climate action. Never before has society had all the smart policy and technology resources to curb greenhouse gas emissions and build resilience,” Christiana Figueres, executive secretary of the U.N. Framework Convention on Climate Change (UNFCCC), said in a statement. “All of this means we can be confident we will have a productive meeting in Lima, which will lead to an effective outcome in Paris next year.”

The U.N.-led negotiations on climate change, which have dragged on for over two decades, come just weeks after the U.S. and China -- which produce almost as much carbon dioxide as the rest of the world combined -- agreed on a bilateral deal to limit the production of greenhouse gases over the next 10 to 15 years.

“This sends an important signal for the rest of the world to come forward as early as possible with their own contributions,” Elina Bardram, the European Union’s chief negotiator, said on Sunday, according to media reports.

Under the previous emissions treaty, adopted in Kyoto in December 1997, 192 countries had agreed to reduce greenhouse gas emissions. However, in 2012, a number of nations, including the U.S., China and India, refused to ratify amendments to the treaty, which would impose legally binding limits on their emissions.

The nearly two-weeks long talks in Lima are expected to focus on drafting a new agreement that will be adopted in Paris next year, the statement released by the UNFCCC said.

The ultimate goal of the talks is to restrict the rise of global temperatures to below 2 degrees Celsius (3.6 degrees Fahrenheit) compared to the pre-industrial (1861-1890) average. However, scientists have reportedly said that the goal is now unrealistic, as average global temperatures have already risen 0.8 degree Celsius and could rise by another 3 degrees in coming years.

“We are no longer in a situation where just cutting emissions is enough. We also need to adapt to climate change where possible, and where it isn't possible, countries need to be compensated in some way,” Samantha Smith, leader of the global climate and energy initiative at World Wildlife Fund for Nature, told Reuters.

However, Figueres expressed optimism that a lasting deal to curb the effects of climate change could still be worked out.

“We have seen an amazing groundswell of momentum building this year. One of the main deliverables of the Lima conference will be ways to build on this momentum and further mobilize action across all levels of society,” she said, adding that immediate action was needed to “safeguard this and future generations.”