For a week in November, 43 states in the US were locked into a below-normal weather pattern. Houses in some northern regions were engulfed by as much as seven feet of snow (2.13 meters), and residents had to dig tunnels to get themselves out. The freakish cold snap is just one example of how extreme weather has become a harsh reality and how urgent it is to combat climate change by controlling greenhouse gas emissions. Apart from devastating floods, wild fires and droughts that have tormented other parts of the world, a huge swath of northeast China is often blanketed in toxic smog.

It's under such a background that 195 countries and regions began talks on Monday in Lima, Peru to lay the foundation for a new climate agreement that would set the course for them to reduce carbon emissions. It will ultimately be signed next year in Paris.

The Lima conference stands at an all-important crossroad. It's of critical importance whether the long-standing impasse over climate talks will end or not.

Enormous obstacles, which have sabotaged negotiations in the past more than two decades, remain. Xie Zhenhua, head of the Chinese delegation, told media before the Lima conference that the thorniest question to be addressed remains whether developed countries could fulfill their obligations in providing developing countries with support for financing, technology and capability building to tackle climate change. Developed countries, especially the US and Europe, are the biggest historic polluters and they should help their poorer counterparts financially to make the transition to renewable energy. However, previous summits have seen them maneuvering to pass the buck and showing great reluctance to make legally binding commitments to cut carbon emissions.

Nonetheless, observers said that there is fresh optimism surrounding the Lima talks. The talks come three weeks after China and the US, two of the world's biggest emitters, declared an agreement on carbon-cutting. Under the deal, China committed to cap its carbon emissions by 2030 or earlier, and to increase the non-fossil fuel share of its energy use to 20 percent, while the US agreed to reduce its emissions by 26 percent and 28 percent from their 2005 levels by 2025.

It's high time that other countries follow suit. The world is still way short of the level of carbon-cutting action needed to address what some have described as the greatest environmental peril in history. It's reported that at the opening session on Monday in Lima, several diplomats pleaded for unity in tackling climate change. Without unity and the sincerity to compromise, we cannot expect a breakthrough in the Lima talks.