Mr Brown was speaking after talks at Downing Street with Mr Barroso
Plans for a higher road tax on the most polluting cars are part of a "long-term trend" in many countries, Prime Minister Gordon Brown has said.
He said there were widespread moves to "discourage high-polluting vehicles" abroad and urged more research into "commercially viable" electric cars.
The Tories say the new tax, due to start next year, will be "deeply unpopular" as it includes older cars.
Later Lib Dem Vince Cable said it would bring green taxes "into disrepute".
New vehicle excise duty bands aimed at penalising the highest-polluting cars are due to come into force next spring.
'Long term trend'
Ministers argue the new tax bands would save 1.3 million tonnes of carbon dioxide emissions by 2020, but concerns have been raised because they will apply not just to new cars, but also to those registered since 2001.
Many Labour MPs are concerned it will hit poorer people with old cars.
At a press conference with European Commission Jose Manuel Barroso, the prime minister said easing the burden of high food and fuel prices on families would be a priority at a summit later this month.
But asked if he would rethink changes to vehicle excise duty, he said: "There's been a long-term trend where people wish to move to encourage low polluting vehicles and wish to discourage people with new incentives for high-polluting vehicles.
"That is a trend that is happening in every country as a result of what's happening both to the cost of fuel and to people's desire for greater fuel efficiency."
Mr Brown also said he wanted to see manufacturers encouraged to design more efficient cars alongside a commitment from European leaders to explore the potential of new technologies like developing a "commercially viable" electric vehicle.
Under the new vehicle excise duty system, owners of the most polluting cars would pay £440 in tax.
And from April 2010, people buying the most polluting cars would pay a one-off "showroom tax" of up to £950.
Mr Brown says that 24 of the top 30 models of car would incur the same vehicle excise duty or lower - Tory leader David Cameron has accused him of using "dodgy statistics".
In the Commons earlier, Treasury minister Angela Eagle said the new VED reforms would "send strong signals to motorists to purchase more fuel-efficient new and second-hand cars".
But later Lib Dem deputy leader Mr Cable, told BBC One's Question Time: "It isn't fair and it isn't sensible and it's bringing environmental taxes into disrepute.
"I think it's cynical, it's very short sighted and it's left people with a bad taste in their mouths."
Some Labour MPs are concerned that the tax change will hit people with older cars and fear it could create a backlash similar to that created by the abolition of the 10p income tax rate.
But Foreign Secretary David Miliband told the programme about 60% of people would pay less vehicle excise duty under the new plans.
"I feel we have got a simple principle here which is that greener vehicles are going to pay less," he said.