COP26: What is it and why is it the world's last chance for climate action?

The UN climate summit, known as COP26 this year, has opened in Glasgow. It brings officials from almost 200 countries to haggle over the best measures to combat global warming.

COP, short for Conference of the Parties to the UN Framework Convention on Climate Change, is in 26th year since the first summit in 1995. So COP26.

Even after realising so long ago the very imminent threat to climate, the world leaders are still arguing over how to combat the greatest threat to Earth.

So what is it that needs to get done.

In Paris in 2015, nations agreed to keep the temperature increase below 2 degree Celsius above pre-industrial levels. The world leaders agreed that the ideal would be 1.5 degree Celsius.

But humans have already heated the planet 1.1 degrees and global temperatures are very likely to rise 1.5 degrees Celsius above pre-industrial levels in the next few decades.

The world is way behind the commitments and we are heading for a 2.7 degrees increase.

These increasing temperatures will see more extreme weather events occurring more often -- more hurricanes, more flooding, more fire, more drought.

Then there is the issue of Climate Finance. Who will pay for the developing countries' transition to clean energy when the big, developed nations have plundered climate for growth?

The biggest emitters of carbon are China, the US, India, Russia and Japan. The European Union countries altogether rank as the third biggest. Poor countries didn't contribute the same level of emissions -- yet they are the major victims of the climate crisis.

The wealthy nations pledged $100 billion a year to poor countries by 2020, which didn't happen.

COP26 is set to be a big moment for upholding and strengthening these pledges.

While COP26 is being hailed as the best last chance to avert catastrophe, what will it take for the summit to succeed?

The nations need to pledge to zero emission by 2015 and a big reduction by 2030 at COP26 for it to have a meaningful impact.

The developing nations will want a financial package to adapt to clean energy.