Image caption Campaigners criticised the low priority given to temperature rise in the report

The International Energy Agency (IEA) has infuriated environmentalists with a report on what it calls the "golden age" of gas.

The summary says gas use could grow more than 50% by 2035 if local problems with shale extraction can be overcome.

Only in the last paragraph does it say this would be inconsistent with a global temperature rise of 2C.

And it does not warn the boom could lead to a potentially devastating 3.5C rise until page 91 of the full report.

Critics complain that most policy makers won't get that far and say the IEA should not be celebrating any fossil fuel golden age.

Tony Bosworth, of Friends of the Earth, told BBC News: "The 'golden age' for gas risks leading to temperature rises that will be catastrophic," he said.

"If we're talking about golden rules, we need one to protect the world's climate."

"The IEA should be making that top priority not hyping the prospects for the gas industry. If we get a boom in gas that'll starve investment from the clean energy sources we really need."

Full disclosure

The report is designed to codify rules for governments in many countries coping with a welter of applications to drill for coal bed methane or use fracking to liberate shale gas or other tight (trapped) gas.

The threat of climate change is right at the top of our agenda Fatih Birol, Chief economist, IEA

It backs many demands from environmentalists, including a stipulation that fracking firms must use less water; measure and disclose data on water use, waste water, methane and other emissions; solve air pollution problems; and minimise leakage of methane.

Importantly, it demands that firms should face full, mandatory disclosure of the chemicals in the fracking process - something that drillers in the US have resisted under commercial confidentiality. The UK Environment Agency has already announced that it will require disclosure of fracking fluids.

The report urges governments worldwide to ensure that the expected growth in gas is matched by a growth in cash and political support for regulators.

Media playback is unsupported on your device Media caption Extracting gas from shale rock in the US

It says if these can be achieved, the world is ready for a golden age of gas. A boom in unconventional gas would keep greenhouse gases 1.3% lower than a scenario in which use of unconventional gas were restricted.

The IEA report does not foresee widespread adoption of carbon capture and storage (CCS) from gas-fired powered generation by 2035.

The IEA's chief economist Fatih Birol said criticism of the report was unfair: "We are not saying that it will be a golden age for humanity - we are saying it will be a golden age for gas, but only if problems with fracking are overcome.

"I see communities who seem to me to have legitimate concerns about water pollution, land use and flaring. These will be a roadblock to shale gas unless governments can impose best practice in a clear and transparent way.

"We see in some countries shale gas is already substituting for coal and that is welcome as it reduces CO2. But this will only help slow growth in CO2, not bring us to a desired trajectory.

"The threat of climate change is right at the top of our agenda - we just announced a record CO2 level for the world and we are warning that we are almost ready to shut the door on a trajectory towards a 2C temperature rise."

Today's IEA report forecasts that if unconventional gas overcomes concerns, the growth in demand for gas would equal to growth from coal, nuclear and oil combined, keeping gas prices down.

It would also outstrip the growth of renewables and by 2035 gas would overtake coal to become the second largest source of primary energy after oil.

Dr Birol previously told BBC News that the gas boom was likely to divert investment from renewables.

The sudden unpredicted glut of global gas has changed the energy landscape. A few years ago many governments had been persuaded that energy security and climate security were inextricably linked.

Now major players like the US are in the process of achieving energy security more cleanly than they would have from coal, but less cleanly than from renewables.

In the UK, the Environment Agency chairman Chris Smith has given a reluctant go-ahead to shale gas, provided that it's fitted with CCS.

The Committee on Climate Change says the UK should not generate more than 10% of its electricity from gas by 2030 unless it has CCS.