Merkel told Petersburg Dialog talks in Berlin involving environment ministers of 35 nations that climate change was a "fact" and the clamor from children and youth to avert "catastrophe" was understandable.

Referring to a nine EU-nation initiative led by French President Emmanuel Macron and broached last week at the EU's summit in Sibiu, Romania, Merkel on Tuesday said her ministers grouped within a special "climate cabinet" had yet to decide on the matter.

"The discussion is not about whether we can achieve it, but about how we can achieve it," said Merkel, a trained physicist, adding: "if we can find a sensible answer, then we can join the initiative."

Read more: Schulze urges Merkel to join Macron's EU climate initiative

Carbon dioxide "neutrality" by 2050 assumes a stable sum between atmospheric greenhouse gases emitted and absorbed; especially carbon dioxide from burning fossil fuels, offset through absorption via vegetation, for example, carbon being transfixed as wood.

Such neutrality, said Merkel, would still allow for carbon dioxide to be emitted but stored or compensated for through measures such as forest plantings.

Referring to September's planned climate conference in New York, to be chaired by UN chief Antonio Guterres, Merkel said: "We acknowledge our responsibility."

Political will 'fading'

Visiting New Zealand on Sunday, Guterres had warned that political will to tackle climate change was "fading" as things got worse.

Alluding to the global Fridays-for-Future movement, Merkel said the clamor by children and youth to avoid a climate "catastrophe" into their adult lives was "understandable" and "we should take it up."

A warning from the UN's Food and Agriculture Organization (FAO) about an insufficient global 2018/2019 wheat harvest - due to heatwaves and drought — exemplified how the world was eating into its "reserves," she said.

'Shameful group' within EU

Ahead of Tuesday's Berlin conference, Greenpeace International chief Jennifer Morgan, on a visit to South Korea, urged Merkel to again take an EU-lead on climate she had shown in previous years.

"Germany must take the lead again instead of being part of the shameful group in the EU that is blockading," said Morgan, while urging Germany to rapidly rid itself of coal blamed for climate-warming carbon dioxide.

'Keeling Curve' at historic high

It has reached 415 parts per million (ppm), the highest level ever in human history, according to Monday's announcement from the Scripps Institution of Oceanography, a US center that has monitored CO2-levels on Hawaii's Mauna Loa since 1958.

The rise year-on-year was at the "high end," said Scripps director Ralph Keeling, whose rising "Keeling Curve" diagram is closely watched by climatologists.

Earth science analyses show that the atmosphere last contained this much CO2 some three million years ago, when global sea levels were higher and parts of Antarctica were blanketed in forest.

Already, one degree up

At the 2015 Paris climate summit, most world nations agreed that the world's atmospheric temperature rise should be kept at 1.5 degrees Celsius, if possible, and "well below" 2 degrees, compared to pre-industrial levels.

The earth's average surface temperature has already risen by 1.0 degrees Celsius.

The Petersberg Climate Dialog, held for the 10th time this week in Berlin, refers to a hilltop hotel complex overlooking Bonn — the seat of the UN's Climate Secretariat — where talks were resumed after the failed 2009 UN Copenhagen climate summit.

ipj/rc (dpa, Reuters, AFP)