After nearly three decades of dancing around the chief driver of global warming, UN climate negotiations in oil-rich United Arab Emirates on Wednesday called for the first time for the world to "transition away" from polluting fossil fuels.

The landmark first for the UN process was laid out in a text designed to respond to the failure so far to meet the Paris deal's more ambitious -- and safer -- goal of limiting global warming to 1.5 degrees Celsius from preindustrial levels.

The UN's IPCC climate science panel and the International Energy Agency have stressed that no new fossil fuel infrastructure is compatible with that target -- yet major coal, oil and gas countries and firms currently plan to keep increasing production.

Agreed by almost 200 countries, the COP28 decision "marks the beginning of the end of the fossil fuel era", said analyst Dave Jones of energy thinktank Ember.

But the text contains some significant loopholes, analysts say.

Here are some key points:

- Fossil fuels -

The key paragraph calls for a "transitioning away from fossil fuels in energy systems, in a just, orderly and equitable manner, accelerating action in this critical decade, so as to achieve net zero by 2050 in keeping with the science".

While UN climate negotiations have mentioned fossil fuels before, this was to call for a phasing out of "inefficient" subsidies.

Tackling all fossil fuels, which account for some three quarters of all human-caused emissions, is "unprecedented in this process" said David Waskow, International Climate Action Director at the World Resources Institute.

Observers said another positive was the call for acceleration "this decade" -- a crucial timeframe given that the IPCC says emissions must be slashed almost in half by 2030 to keep 1.5C in sight.

But they raised concerns that the call to move away from fossil fuels was only within the energy sector, leaving out reference to polluting plastics and fertilisers.

- Renewables -

The Dubai text calls for: "Tripling renewable energy capacity globally and doubling the global average annual rate of energy efficiency improvements by 2030".

At the start of the Dubai meeting, more than 130 countries signed on to a voluntary pledge to do just this, but observers say inclusion in the main COP28 decision text was key.

Momentum has been building for this target, not least because of the dramatic increase in renewable capacity over recent years.

The IEA has forecast that world demand for oil, gas and coal would peak this decade thanks to the "spectacular" growth of cleaner energy technologies and electric cars.

In September, the G20 -- accounting for some 80 percent of global greenhouse gas emissions -- broke new ground in endorsing the goal of tripling renewable energy capacity by the end of the decade.

"For the first time, the world has recognised the scale of ambition required this decade to build the new clean energy system: a tripling of renewables and doubling of efficiency improvements," said Jones.

"Together they are the single largest actions that can deliver rapid fossil fuel cuts this decade."

- Coal -

The first push for an agreement on stopping burning fossil fuels came at the Glasgow climate conference two years ago, where negotiators singled out coal.

That meeting ultimately agreed to "phasedown" unabated coal power -- meaning without technology to capture emissions.

Coal is the dirtiest fossil fuel, but it is also a mainstay of many energy systems in developing economies, including in India and China.

Negotiators in Dubai retained this language.