A peak in global energy-related emissions could be achieved as early as 2020 and at no net economic cost, the International Energy Agency said, warning that without stronger action the world is set to see a temperature rise of 3C by end of century.

In its new World Energy Outlook Special Report on Energy and Climate Change released on 15 June, the IEA proposes four key pillars for a successful climate pact and five policy measures to achieve the peak energy-related emissions.

The IEA's 'Bridge Scenario' for energy peaking identifies energy efficiency improvements in the industry, buildings and transport sectors, while clamping down on least-efficient coal-fired power plants.

Increasing investment in renewable energy technologies in the power sector from $270 billion in 2014 to $400 billion in 2030, gradual phasing out of fossil-fuel subsidies to end-users by 2030 and reducing methane emissions in oil and gas production can all together help achieve peak emissions, the IEA calculates.

World greenhouse-gas (GHG) emissions from energy production and use are double the level of all other sources combined.

"Any climate agreement reached at COP21 must have the energy sector at its core or risk being judged a failure," said IEA chief economist Fatih Birol.

A first assessment of national pledges, or 'Intended Nationally Determined Contributions' (INDCs) reveals these pledges fall short of the major course correction required to meet the 2C goal.

Growth in global energy-related emissions slows but does not peak by 2030. While the link between economic growth and emissions weakens significantly, it is not broken. The economy grows by 88% from 2013 to 2030 and energy-related carbon dioxide emissions by 8%.

Renewables are the leading source of electricity by 2030, but inefficient coal-fired power generation capacity declines only slightly, notes IEA.

Review and tracking of climate actions

For the climate pact in Paris later this year the agency identifies four key pillars from an energy perspective.

Besides setting conditions for an early peaking in energy-related emissions, the COP21 must insist on a five-year review that allows national targets to keep up with the changing climate situation and help build investor confidence.

A long-term greenhouse-gas emissions target to guide investment decisions, provide an incentive to develop new technologies, drive needed market reforms and spur the implementation of strong domestic policies, such as carbon pricing, will help meet the 2C goal.

Tracking national progress is also important to reassure the international community on action taken and to identify countries struggling with implementation.