The UN climate summit in Paris has some tough nuts to crack: With global temperatures and CO2 emissions breaking records, greenhouse gas cuts pledged so far will not keep global warming to the agreed-upon limit.
Britain's Met Office recently announced that average global increase in temperature is likely to pass the milestone of 1 degree Celsius above pre-industrial levels by the end of 2015 - halfway to the 2-degree Celsius (3.6-degree Fahrenheit) limit that international experts agree is the highest the world can afford, if catastrophic impacts from climate change are to be averted.
Meanwhile, a report by the World Meteorological Organization said that greenhouse gas levels in the atmosphere reached a record high in 2014.
Ahead of the key COP21 meeting in Paris, United Nations climate chief Christiana Figueres and Jochen Flasbarth from the German Ministry for the Environment presented a report synthesizing the effects of countries' intended nationally determined contributions (INDCs) in Berlin at the end of October.
These INDCs are climate action plans submitted by governments ahead of the 21st Conference of Parties in Paris (November 30 to December 11).
As of November 24, 175 countries have submitted climate pledges, covering 97 percent of global emissions. The question remains whether this will be enough.
3 degrees on the horizon?
Putting all pledges together on the table, it becomes clear this will not be enough to limit global warming to the internationally set target of a maximum 2-degrees Celsius temperature rise.
"The INDCs have the capability of limiting the forecast temperature rise to around 2.7 degrees Celsius by 2100," UNFCCC Executive Secretary Christiana Figueres said in Berlin upon release of a summary report in October. She acknowledged this was "by no means enough."
But Figueres added that the pledges submitted to date are "a lot lower than the estimated 4, 5 or more degrees of warming projected by many prior to the INDCs."
The UN is keen to stress that the INDCs are "not the final word," but a signal of a global move towards decarbonization, and toward a "climate-safe future."
Figueres told journalists the national climate action plans represent a "clear and determined down payment on a new era of climate ambition from the global community of nations."
But critical voices were also raised, as the UNFCCC aggregation report confirmed a so-called "emissions gap" between what has been pledged so far, and what is still needed to limit global warming to below 2 degrees.
Development organization Bread for the World described the gap between pledges and the 2-degree target confirmed by the new report as shocking.
"It shows that people are evidently taking the risk of heading toward a preventable catastrophe, instead of significantly reducing greenhouse gases," said the group's climate expert Sabina Minninger. She warned that increased extreme weather events would lead to famine, aggravate conflicts and an increase in migration.
Martin Kaiser, head of Greenpeace international climate policy, said in a statement: "What is currently on the table can only keep the temperature rise under 3 degrees at best - and that would be double what those countries demand, that are most under threat from climate change."
Regine Guenther, climate policy director for WWF Germany, stressed the need to focus on closing the emissions gap. The Paris agreement must include a mechanism that forces individual countries to reduce their emissions further - in short intervals of five years, she said in a statement.
At the same time, renewable energy would have to be expanded on a large scale through bilateral and multilateral cooperation.
2-degree target still within reach?
German climate expert Mojib Latif told DW that pledges by the world's top emitters - the United States and China - were not adequate:
"Obama changed the reference year, so normally it should be 1990, but he chose 2005. That is not very honest, because the US has increased its emissions a lot from 1990 to 2005," Latif said. "China is saying they will continue to increase their emissions until 2030, so they are not talking about reductions," he continued.
But Latif and other experts and scientists agree with the UN view that it would still be possible to keep to the internationally agreed climate goal of 2 degrees if countries and industry took more ambitious action.
Latif cites Germany's energy transition as an example: "Nobody expected in the 1990s that we would meet 30 percent of our energy consumption by renewable energies."
Paris: launchpad to a fossil-free future?
Physicist Stefan Rahmstorf from the Potsdam Institute for Climate Impact Research (PIK) told DW global emissions would have to start falling by 2020 at the latest:
"I think that for the risks to the climate system, things are looking more optimistic than they did a few years ago. The development of renewable energies - wind, solar and others - has really surpassed the most optimistic expectations," Rahmsdorf said.
"And so there is hope that if we really put our will to it, we will be able to stop global warming below 2 degrees, and hopefully closer to 1.5 degrees Celsius."
Rahmstorf says although the INDCs are not enough for that target, "they are enough to really make a difference and set us on the right track of falling emissions.
"The hope is rising that Paris will be seen as a turning point, after which emissions start to drop globally, relatively soon," Rahmsdorf concluded.
Jennifer Morgan, global director of the Climate Program at the World Resources Institute, which follows emissions reductions with its own Climate Tracker, told DW the key to success lies in the "long-term vision" of a Paris agreement. She stressed it has to oblige countries to keep upping their commitments, and set a long-term signal for decarbonizing economies.
The year 2015 is expected to be the hottest on record, thanks to a combination of a strong El Nino event and human-caused climate change. Negotiators meeting in Paris carry a huge responsibility, with a rapidly narrowing time window for closing the emissions gap.