Countries' latest pledges to cut their greenhouse gas emissions are still not enough to avoid the most devastating consequences of a changing climate, according to a new analysis.

What's more, the report by Climate Action Tracker finds that of the many pledges to zero out climate emissions, only four have concrete plans to achieve that. They are by Chile, Costa Rica, the European Union and the U.K.

It's the latest assessment to cast doubt on the meeting's rallying cry to "keep 1.5 alive." That refers to the target in the Paris climate agreement to limit global warming to 1.5 degrees Celsius (2.7 degrees Fahrenheit).

The Climate Action Tracker report shows that under the most optimistic scenario, if countries fulfill all the promises they've made so far, warming would be about 1.8 degrees Celsius. That's similar to a new U.N. assessment and an International Energy Agency analysis last week.

But few believe that optimistic scenario is realistic right now, because while countries have pledged things like zeroing out greenhouse gas emissions by 2050, few are on track to do that.

"Glasgow has a serious credibility gap"

The Carbon Action Tracker update also calculated projected warming from current policies that countries are actually carrying out. It found they will lead to warming of 2.7 degrees Celsius (4.86 Fahrenheit) at the end of the century. That's just a 0.2 degrees Celsius improvement over last year.

"Glasgow has a serious credibility gap," says Climate Analytics CEO Bill Hare. He says many countries' emissions targets for 2030 are not ambitious enough to make longer term goals credible.

"It's all very well for leaders to claim they have a net zero target, but if they have no plans as to how to get there," he says, "then frankly, these net zero targets are just lip service to real climate action."

Inger Andersen, Executive Director of the U.N. Environment Programme, was even more colorful in her assessment on Twitter. She said while it's great to see countries submitting more aggressive targets, "the reality is that the sum total of our climate efforts thus far is like an elephant giving birth to a mouse."

There were hopes countries would sign onto bold new pronouncements to phase out climate-warming fuels. Some of the efforts include a fossil fuel non-proliferation treaty and a pledge to end coal use. But even the host country for the talks, the United Kingdom, is considering opening a new coal mine.

Boosting post-Glasgow ambition

As various climate groups held press conferences Tuesday in Glasgow the mood was pessimistic. Scientists say time is running out to avoid catastrophic warning. But climate advocacy also requires optimism. Some said they were encouraged to see additional countries pledging to achieve more ambitious emissions reduction targets.

"Countries must back them up at home and do policy that's necessary to achieve those targets," said Maria Jose de Villafranca, a climate policy analyst at NewClimate Institute.

There are still a few days left of this climate meeting, but some already are looking ahead to future ones.

David Waskow, director of the World Resources Institute's International Climate Initiative, encouraged countries to come back within a couple of years and pledge to enhance their 2030 targets to align with the Paris agreement.

"That's critically important for those that haven't enhanced at all," he says, citing "Saudi Arabia, Mexico, Australia and others."

Waskow also singled out China and Russia as countries that would need to boost their commitments. On Monday, former President Barack Obama criticized Chinese President Xi Jinping and Russian President Vladimir Putin for not joining other global leaders at the climate talks in Glasgow.

For now, the U.S. is among countries with ambitious goals yet no firm plan to get there. President Biden has set a target of a 50-52% reduction in economy-wide greenhouse gas pollution by 2030. But a budget bill designed to accomplish that remains stalled in Congress.