In its annual report, the World Meteorological Organization said concentrations of CO2, methane and nitrous oxide once again broke records in 2014.
"It is just the right moment to introduce carbon taxes," Lagarde said at the annual meetings of the International Monetary Fund and World Bank in Lima, Peru.
The Like Minded Developing Countries (LMDCs) is a formal negotiating group that includes China, India, Malaysia and Indonesia
Merkel and Rousseff focused mainly on environmental cooperation during a 24-hour visit by the German leader that was also aimed at boosting trade and investment in Brazil's stagnant economy.
"President Obama's leadership by example is essential for bringing other key countries on board and securing a universal, durable and meaningful agreement in Paris in December."
The climax of Tuesday's session was the afternoon audience with Francis, who has become a hero to the environmental movement, to focus world attention on climate change and its effects on the poor.
The study also warned around 750 million people in South Asia could face extreme water shortage, or 1.8 billion people could face chronic water shortage by 2050, due to population growth.
France is also acutely conscious of the fact that the previous such move had backfired and Copenhagen meeting had ended in a failure.
On the whole, the church's environmental message has been articulated for years, though it has gotten lost in other issues.
"By 2100 we expect 130 to 160 gigatonnes of carbon released into the atmosphere," Natali told journalists in Bonn.
Climate is one of the key topics on the agenda at a G7 meeting in a Bavarian castle starting on Sunday.
Achieving the 2C target has been the driving force for climate negotiators and scientists, who say it is the limit beyond which the world will suffer ever worsening floods, droughts, storms and rising seas.
Japanese Prime Minister Shinzo Abe made the pledge at a meeting with Pacific island nations in Iwaki in northern Japan.
Figueres said technological advances were the first of several factors that had created "a very changed political environment."
US President Barack Obama said today that climate change poses the world's biggest single threat.
Tokyo will set a target of cutting gas emissions "by at least 20 per cent by 2030, from 2005 levels."
It said that the health impact of climate change on the EU's 500 million citizens is "expected to worsen.''
Water pours into the sea- 130 billion tons of ice per year for the past decade, according to NASA.
"It is important to ensure that the enhanced provision of resources to developing countries for climate change and environmental concerns is additional."
Volcanoes may have caused cooling of 0.05 degrees to 0.12 degrees Celsius since 2000.