"We're not moving quickly enough. We all need to act," Macron said, seeking to breathe new life into a collective effort that was weakened this summer when President Donald Trump said he was pulling the United States out of an international accord brokered in the French capital two years ago.
Modern-day science was revealing with each day the danger that global warming posed to the planet, he said.
"We are losing the battle," he said, urging the assembled heads of states, ministers and executives to launch a new phase in the fight against global warming.
No internationally binding commitments will be made at Tuesday's "One Planet" summit.
In focus is how public and private financial institutions can mobilise more money and how investors can pressure corporate giants to shift towards more ecologically friendly strategies.
More than 200 institutional investors with $26 trillion in assets under management said on Tuesday they would step up pressure on the world's biggest corporate greenhouse gas emitters to combat climate change.
That, they said, would be more effective than threatening to pull the plug on their investments in companies, which include Coal India, Gazprom, Exxon Mobil and China Petroleum & Chemical Corp.
Separately, European Commission Vice President Valdis Dombrovskis said the executive was "looking positively" at plans to reduce capital requirements for environmentally-friendly investments by banks in a bid to boost the green economy.
The move could be part of a broader set of measures the EU plans to present in March to meet the target of cutting carbon emissions by 40 percent by 2030, for which it estimates around 180 billion euros ($212.2 billion) in additional low-carbon investments are needed per year.
Climate change is causing more frequent and severe flooding, droughts, storms and heatwaves as average global temperatures rise to new records, sea ice melts in the Arctic and sea levels rise.
Developing nations say the rich are lagging with a commitment dating back to 2009 to provide $100 billion a year by 2020 - from public and private sources alike - to help them switch from fossil fuels to greener energy sources and adapt to the effects of climate change.
"The missing piece of the jigsaw is the funding to help the world's poorer countries access clean energy so they don't follow the fossil fuel-powered path of the rich world," said Mohamed Adow, charity Christian Aid's lead on climate change.
On Tuesday, the European Commission unveiled 9 billion euros worth of investments targetting sustainable cities, sustainable energy and sustainable agriculture for Africa and EU neighbourhood countries.
Some 50 world leaders and ministers are in Paris, including Mexican President Enrique Pena Nieto and leaders of states at the sharp end of climate change such as Chad, Bolivia and Haiti.
The United States has sent only an official delegation from the Paris Embassy, but screen superstars Leonardo Di Caprio and Arnold Schwarzenegger and California Governor Jerry Brown, leader of the world's sixth largest economy, are championing more action.
In a pointed piece of timing, Macron used the eve of the summit to award 18 grants to foreign climate scientists, most of whom are currently U.S.-based, to come and work in France.
Paris climate summit sets scene for greener investment
In the same vein, a "One Planet" summit on Tuesday in Paris - led by France's President Emmanuel Macron, as well as World Bank and U.N. chiefs - aimed to accelerate lagging efforts to combat climate change.
The gathering, which drew a range of green investment pledges, focused on ways to raise more money for climate action and how to pressure corporate giants to shift towards more climate-friendly strategies.
Campaigners welcomed promises made around the summit - which marks two years since the Paris Agreement was adopted - but said much more action is needed.
Here are some views from government officials, climate researchers and activists on the outcomes of the meeting:
Allen Chastanet, prime minister, St. Lucia
"Ultimately, we will only win the battle on climate change when investments in climate action and broader resilience become the economically sensible decision to make every time.
"It's not just about protecting against negative impacts – climate action needs to be about enhancing competitiveness, creating jobs, improving our economies. Otherwise, our people cannot make the sacrifices needed."
Shelagh Whitley, head of climate and energy, overseas development institute
"The World Bank Group is finally showing true leadership on climate change with their announcement today that they will end all finance for the extraction of fossil fuels by the end of 2019.
"All multilateral and bilateral public finance institutions must now follow the example set by the World Bank Group and end wasteful and dangerous government support to dirty fossil fuels."
Nick Mabey, ceo, e3g
"The success of the One Planet Summit shows the world has moved past Trump and is focusing on delivering the Paris Agreement. The sheer amount of announcements at the Summit prove smart finance is moving out of fossil fuels and into the clean economy. We must now follow through to make sure governments, businesses and financial institutions increase their climate ambition to 2020 and beyond."
Gyorgy Dallos, campaigner, greenpeace international
"The end is clearly coming for the oil and gas industry as the pace of change accelerates. After Norges Bank's historic announcement (urging the Norwegian government to divest its trillion-dollar sovereign wealth fund from fossil fuels), the World Bank – as one of the world's most powerful financial institutions – has sent a damning vote of no confidence to the future of the fossil fuel industry.
"The world's financial institutions now need to take note and decide whether their financing is going to be part of the problem or the solution."
Catherine Abreu, executive director, climate action network canada
"High-level summits are only as good as the actions they generate, and the world will be watching to see to what extent momentum is increased to shift financial flows and mobilise the trillions of dollars in climate finance required.
"Now attention must turn ... to phasing out fossil fuel subsidies. Countries can't adequately fund climate solutions while they continue to fund the problem."
Manuel Pulgar-vidal, climate and energy leader, wwf
"Initiatives, such as this summit hosted by President Emmanuel Macron, are important to keep our leaders committed, political will high and momentum in scaling and speeding up new and existing climate actions across all actors."
"This is critical if we are to keep warming below 1.5 degrees Celsius and avoid the worst impacts of climate change."
Mary Robinson, chair, foundation - climate justice
"Climate justice is all of our responsibility. We must stand alongside all the people of the small island nations who will be most impacted by climate change.
"The recent hurricanes in the Caribbean have been devastating to watch, with people still homeless, without electricity and without livelihoods.
"We need to provide support in the form of immediate relief, and we also need to start working with them to build a resilient future where the people of the Caribbean can thrive."
Sven Harmeling, climate change advocacy coordinator, care international
"CARE welcomes the One Planet Summit where promising announcements were made to move away from fossil fuels to help slow down the escalation of climate change, such as by the World Bank and the insurance company AXA.
"However, we are disappointed by the lack of commitments from developed countries for adaptation finance which is necessary to help vulnerable people, especially women and girls, prepare for climate change impacts such more severe floods and droughts."
"Nations and private donors must step up their ambition in 2018."
Mohamed Adow, international climate lead, christian aid
"Today's summit in Paris, the birthplace of the agreement that offers us the best chance to save the planet, has sent a clear message to the world that countries, states, cities, businesses and civil society are firmly committed to their Paris commitments and are coming good on their promises, with or without the United States.
"Where there is political will, money flows, and this summit has started to see that crucial green finance uncorked. The global demand for clean technology is a great investment opportunity for private investors but also for development banks and leaders that want to see their countries prosper."
Harjeet Singh, climate lead, actionaid international
"Plenty of sympathy was expressed for the countries suffering from extreme climate events. Unfortunately, sympathy doesn't cover costs for vulnerable communities overwhelmed with climate impacts. The world needs major mobilisations of public finance to cope with the scale of the challenge.
"While action by businesses is needed, governments need reminding that they can't fix climate change by giving up their responsibilities and letting business dictate the entire climate agenda."
Karen Orenstein, deputy director of economic policy, friends of the earth
"The exploitation of oil and gas, in addition to coal, is an affront to the World Bank's long-claimed goals of poverty alleviation and sustainable development. While the World Bank's decision to finally end the financing of upstream oil and gas after 2019 is long overdue, it is certainly worth celebrating.
"The policies and practices of the World Bank send a strong signal for finance institutions worldwide. We now expect all other public and private finance institutions to follow the World Bank's lead and end fossil fuel financing once and for all."
Erik Solheim, executive director, united nations environment programme
"The largest untapped potential for climate action is in how we manage our land and soils.
"We need to design sustainable agriculture and forestry in a way that solves the climate crisis, rather than contributes to it."
"Right now, less than 3 percent of climate finance, public or private, goes to sustainable land-use - and yet it can be more than 30 percent of the solution. We need a tenfold increase in climate finance that goes to sustainable land-use”