Former British Prime Minister Tony Blair said in Beijing on Wednesday the world should fend off a tendency of erecting trade barriers in the name of environmental protection and meanwhile should not relent in fighting global warming because of economic recession.

"The worst response will be to be protectionist, either by front door or back door. That is not the way to resolve this (climate change) or the economic crisis," said Blair during a visit here at the invitation of the Chinese People's Institute of Foreign Affairs.

"What we've got to watch is protectionism by the back door, using environmental standards ... as a way of effectively keeping out other nations' goods," said Blair in an interview.

His comment came after the US Energy Secretary Steven Chu said last week he advocated a carbon tariff on imports from countries that don't have mandatory carbon emission reductions once the Obama administration implements its plan of limiting carbon emissions.

Blair, also initiator of the Climate Group (TCG), a British-based non-governmental environmental advisor, didn't specifically refer to the US announcement but said tariffs are "also back-door protectionism" and are "wrong."

While explicit protectionism is "unlikely," the back-door kind will be "a very difficult part of the discussions" about tackling climate change and financial crisis, said Blair.

The World Bank said last week in a report that 17 of the Group of 20 (G20) developed and emerging economies have implemented measures that restrict trade at the expense of other countries since last November, when the G20 leaders promised to avoid protectionist moves to prevent the faltering world economy from further worsening.

"It's very important that we take a firm stand against protectionism," said Blair, who underscored the significance of pushing forward the world trade talks.

Despite the economic downturn, countries should not delay the action of promoting a low carbon future as climate change is plaguing the world with or without the crisis, said Blair.

He noted the US president Obama's call to reduce the country's greenhouse gas emissions to their 1990 levels by 2020 is a big progress but some concerns within the US Congress need to be resolved.

Some US senators are "skeptical and difficult to persuade" about the emission reduction targets, said Blair, talking about his communications with US senators in Washington earlier this month.