They aim to establish rules, figure out financing and build ways to verify that nations are meeting their commitments.
Over the weekend, 19 G20 member states reaffirmed their commitment to the Paris climate accord - except for the U.S., which pulled out of the landmark agreement past year.
"Katowice (Poland) may show us if there will be any domino effect", from the USA withdrawal, Laurence Tubiana, CEO of the European Climate Foundation and an architect of the Paris agreement, said in the AFP report.
Citing various alarming UN reports including one on rising global Carbon dioxide emissions and another one on increasing greenhouse gas concentrations in the atmosphere he called on nations to pay attention to the science and step up their pace as well as their ambitions.
The two-week conference in Poland's southern coal-mining region of Silesia is expected to work out how governments can report on their efforts to reduce greenhouse gas emissions and keep global warming within the limits of the Paris climate deal.
Such a move, which experts say is the only way to achieve the 1.5-degree goal, would require a radical overhaul of the global economy and a move away from using fossil fuels.
Thousands of people marched in Brussels on Sunday to "Claim the Climate" in a demonstration ahead of the COP24 climate conference.
"If we don't take action", he continued, "the collapse of our civilizations and the extinction of much of the natural world is on the horizon".
"The good news is that we do know a lot of what we need to be able to do to get there", said David Waskow of the World Resources Institute.
UN Secretary General Antonio Guterres delivers a speech during the opening of COP24 UN Climate Change Conference 2018 in Katowice Poland Monday Dec
Ministers and some heads of government are to join Monday, when host Poland will push for a joint declaration on ensuring a "just transition" for fossil fuel industries facing closure as part of efforts to reduce greenhouse gas emissions.
"We are already seeing increased impacts of climate change in China", says a young woman.
But United States President Donald Trump's decision to withdraw from the Paris accord has dented trust among vulnerable nations, who fear there is not enough cash available to help them adapt to our heating planet.
His comments were supported by the UN Secretary-General, António Guterres, who said for many, climate change is already a matter of life and death and that more action needs to take place now.
A key issue up for debate is how the fight against climate change is funded, with developed and developing nations still world's apart in their demands.
He added the Paris agreement was not enough and that more must be done.
The World Bank on Monday said it was doubling funding for poor countries preparing for climate change to $200 billion over five years.
"We will see what comes out of it, because a conference is a conference but what is really important is what is actually done, the actions", she said.