The COP26 Coalition, a UK-based action group, has described the agenda for the UK-hosted climate conference as "woefully inadequate", and says the UK should be leading by example rather than continuing to support fossil fuels and expand air travel.
Speaking at the Unesco World Heritage Centre in Paris on Tuesday, Mr Sharma said: “Responsibility rests with each and every country.
“And we must all play our part. Because on climate the world will succeed, or fail, as one."
He said the Paris Agreement was “a landmark in the global efforts to tackle climate change” but it was just “the beginning of the road”.
He stressed the importance of the COP26 summit, which is being hosted by the UK in Glasgow in fewer than three weeks’ time, saying it must “honour the promises” made in the French capital at COP21 in 2015.
He called on G20 leaders to “step-up” and commit to emissions reductions that would restrict world temperature rise to the 1.5C goal set out in the treaty.
He urged countries to consign coal power to history, accelerate the move to electric vehicles, end deforestation and slash methane emissions.
But COP26 Coalition member Asad Rehman said: “The window on preventing runaway climate disruption is rapidly closing, yet we have nothing on the table which will actually tackle this crisis.
“It’s not tough talking on climate or appeals to others to act that will deliver the outcome needed at COP26 for people and planet.
“The UK should be leading by example, doing its fair share of effort and supporting less well off countries who are bearing the brunt of the climate crisis right now.
“Instead, the UK is digging for more gas and oil, pouring billions into the hands of fossil fuel giants and green lighting more airport expansion.
“Alok Sharma would do well to read his own briefings on climate science and convince the UK Government to focus on action and not hollow promises and pointing fingers.”