The German chancellor called for greater international cooperation, and assured developing countries of financial support. France's Emmanuel Macron and Britain's Boris Johnson were also set to attend the online talks.
The world has already begun to feel the effects of climate change with widespread flooding, droughts and extreme weather
Political leaders from around the world appeared online for the first Climate Adaptation Summit on Monday aimed at preparing the planet for the effects of the climate crisis.
The list of speakers included German Chancellor Angela Merkel, French President Emmanuel Macron and British Prime Minister Boris Johnson. The summit is being hosted by the Netherlands.
In a video message posted ahead of the summit, Merkel called for greater international cooperation and a coordinated response.
"Mitigating climate change and its impacts is made easier if we trust that we are all pulling in the same direction in a spirit of partnership around the world," she said.
She also assured poor countries of financial support in tackling the effects of climate change.
"For Germany, I can say: we are pitching in," she said. Germany has pledged €50 million ($60.7 million) to the Adaptation Fund, to improve developing countries' access to climate-related financing, as well as another €100 million to the least developed countries.
Meanwhile, French President Emmanuel Macron called on leaders to re-evaluate infrastructure systems in the face of rising sea levels.
"In the North and in the South, we must rethink infrastructures, roads, ports in view of rising sea levels, violent weather events, the rise in average temperatures and related changes in the ecosystem," he said.
"In the spirit of the Paris Agreement, we must be ambitious and solidary," Macron added. "This is our collective and individual responsibility."
Bangladeshi Prime Minister Sheikh Hasina said the country is the "ground zero of climate change" and touted locally-led movements to mitigate climate impacts.
"We are promoting locally led adaptation that can bring food and tangible solutions for the vulnerable communities in different countries of the world," she said.
One of President Joe Biden's first acts after entering the Oval Office was to sign an executive order to bring the US back into the Paris Agreement.
And the United States' newly-appointed Envoy for Climate, John Kerry, said at the summit: "We're proud to be back (in the Paris climate accord). We come back, I want you to know, with humility, for the absence of the last four years, and we'll do everything in our power to make up for it."
Kerry said the new administration is working on plans to implement ambitious targets for cutting emissions.
Outlining the White House's determination to promote climate adaptation, Kerry said it will "leverage US innovation and climate data'' to better understand and manage climate-related risks.
Kerry said last Thursday he saw the Donald Trump presidency as "wasted years" when little was done to slow climate change.
The host nation launched the event by announcing a pledge to pump €20 million ($24 million) into a fund to help the world's least-developed nations adapt to changes related to the climate.
A further €100 million has been earmarked to support sustainable farming in Africa's Sahel region.
The current and former heads of the UN Antonio Guterres and Ban Ki-Moon are also taking part in the meeting in order to produce an "adaptation action agenda."