Poor nations must make haste to curb greenhouse gas emissions as even an impossible zero-percent pollution target for the developed world by 2030 won't stop calamitous climate change, a report warned Tuesday.

Co-authored by former World Bank chief economist Nicholas Stern, the document said that while rich countries are responsible for the bulk of Earth-warming gas emissions since the industrial age, the world could not afford to play the blame-game.

All countries, rich and poor, were moving "recklessly slow" on reducing emissions, said the report issued on the sidelines of UN climate talks in Doha, Qatar.

"There is a deep inequity in that rich countries grew wealthy on high-carbon growth, and poor countries will be hit particularly hard by climate change," it said.

"Recognition of that inequity must play a strong part in building international collaboration, but must not be allowed to block progress: that would be the most inequitable of all outcomes".

The latest round of notoriously tough UN climate talks has seen negotiators bickering in Doha over cash and commitments needed to curb greenhouse gas emissions even as the alarm is being raised anew about the perils the planet faces.

Poor countries insist that Western nations sign up to deeper, more urgent cuts and commit to a new funding package from 2013 to help them cope with worsening drought, flood, storms and rising seas.

The UN goal is to limit global warming to two degrees Celsius (3.6 deg Fahrenheit) -- a level at which scientists believe we may yet avoid the worst effects of climate change.

The paper published by the Grantham Research Institute on Climate Change and the Environment and the Centre for Climate Change Economics and Policy is the latest to suggest this target will be hard to reach.

"At best, global emissions will plateau at around 50 billion tonnes of carbon-dioxide-equivalent per year over the coming decades, with a strong possibility they will go much higher.

"The scale of the risks from these levels of emissions is immense, with likely changes in climate way beyond the experience of modern civilisation."

But there is also a ray of hope, the report said -- accelerating the pace of change towards a low-carbon, resource-efficient economy is still feasible.

For a reasonable chance at making the 2C target, greenhouse gas emissions must fall from about 50 billion tonnes per year now to less than 35 billion tonnes in 2030.

Yet on current patterns, developing countries would probably spew out 37-38 billion tonnes in 2030 compared to rich country emissions of about 11-14 billion tonnes -- about two thirds of the total.

In 1990, the baseline from which the UN has set emission cuts for about 40 rich nations and the European Union, developing nations' contribution was only about one third.

China has since 1990 become the world's biggest emitter of CO2, while India moved ahead of Russia in 2011 to become the world's fourth-biggest polluter, according to the International Energy Agency (IEA).

Neither China nor India, due to their developing nation status, has binding emissions curb targets under the Kyoto Protocol -- nor has the world's second biggest carbon spewer, the United States, which refused to ratify it.

"The arithmetic for a 2C emissions path is stark: stronger action will be required from developing countries, even if developed countries reduce their emissions to zero by 2030," said the report.

It urged closer cooperation, with developing nations setting their own sustainable development agendas, supported by rich countries with know-how, technology and finance.

In 2006, economist Stern authored one of the most influential reports in the history of climate change -- warning it could cost the world at least five percent of gross domestic product (GDP) each year.