A new report on the global energy sector has found it can achieve net zero emissions by 2050 but warns it has a narrow pathway to get there and it will need massively increased investment in clean energy technologies.

The International Energy Agency's Net Zero 2050, a Roadmap for the Global Energy Sector Climate, warns that even if governments meet all their current climate targets this would fall well short of giving the world an even chance of limiting global heating to 1.5C.

It says most of the reductions in CO2 emissions between now and 2030 will come from technologies readily available today. But in 2050, almost half the reductions come from technologies that are currently only at the demonstration or prototype phase.

The IEA says government support for research and development must be increased and the focus should shift from established technologies to new platforms that are still in the early stages of development. It says hydrogen, bioenergy and carbon capture technologies need to be prioritised.

It argues that progress in the areas of advanced batteries, electrolysers for hydrogen, and direct air capture and storage can make a particular impact.

The IEA says providing electricity to around 785 million people who have no access to it and clean cooking solutions to 2.6 billion people who lack them is an integral part of the roadmap's net zero pathway. It estimates this to cost around $40 billion a year, equal to around 1% of average annual energy sector investment.

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It would bring major health benefits through reductions in indoor air pollution, cutting the number of premature deaths by 2.5 million a year.

The roadmap projects that by 2050 global energy demand will be around 8% smaller than today, but serve an economy more than twice as big and a population with 2bn more people. Almost 90% of electricity generation will come from renewable sources, with wind and solar PV together accounting for almost 70%.

Most of the remainder will come from nuclear power. Solar will be the world's single largest source of total energy supply. Fossil fuels will fall from almost four-fifths of total energy supply today to slightly over one-fifth.

Fossil fuels that remain will be used in goods where the carbon is embodied in the product such as plastics, in facilities fitted with carbon capture, and in sectors where low-emissions technology options are scarce.

"Our Roadmap shows the priority actions that are needed today to ensure the opportunity of net-zero emissions by 2050 - narrow but still achievable - is not lost," said Fatih Birol, the IEA Executive Director.

"The scale and speed of the efforts demanded by this critical and formidable goal - our best chance of tackling climate change and limiting global warming to 1.5C - make this perhaps the greatest challenge humankind has ever faced."

"The IEA’s pathway to this brighter future brings a historic surge in clean energy investment that creates millions of new jobs and lifts global economic growth.

"Moving the world onto that pathway requires strong and credible policy actions from governments, underpinned by much greater international cooperation."