Pachauri, who last year earned a joint share of the Nobel Peace Prize, and was re-elected the panel's chairman for a second six-year term last week, told The Observer that diet change is important because of the huge greenhouse gas emissions and other environmental problems - including habitat destruction - associated with rearing cattle and other animals. It was relatively easy to change eating habits compared to changing means of transport, he opined.
According to The Observer and The Guardian, the UN's Food and Agriculture Organisation (FAO) has estimated that meat production accounts for nearly a fifth of global greenhouse gas emissions. These are generated during the production of animal feeds, for example, while ruminants, particularly cows, emit methane, which is 23 times more effective as a global warming agent than carbon dioxide.
The agency has also warned that meat consumption is set to double by the middle of the century.
"In terms of immediacy of action and the feasibility of bringing about reductions in a short period of time, it clearly is the most attractive opportunity," said Pachauri.
"We really have to bring about reductions in every sector of the economy," he added.
Pachauri, who is here to attend an event hosted by animal welfare group -- Compassion in World Farming -- has calculated that if the average UK household halved meat consumption that would cut emissions more than if car use was cut in half.
The group has called for governments to lead campaigns to reduce meat consumption by 60 per cent by 2020.
The average person in the UK eats 50g of protein from meat a day, equivalent to a chicken breast and a lamb chop - a relatively low level for rich nations but 25-50 per cent more than World Heath Organisation guidelines.
Chris Lamb, the head of marketing for the pig industry group BPEX, said the meat industry had been unfairly targeted and was working hard to find out which activities had the biggest environmental impact and reduce those. Some ideas were contradictory, he added.
"Climate change is a very young science and our view is there are a lot of simplistic solutions being proposed," he said.
Last year, a report into the environmental impact of meat eating by the Food Climate Research Network at Surrey University claimed livestock generated eight per cent of UK emissions.
But it also said that eating some meat was good for the planet because some habitats benefited from grazing. It also said vegetarian diets that included lots of milk, butter and cheese would probably not noticeably reduce emissions because dairy cows are a major source of methane, a potent greenhouse gas released through flatulence.