Moves to cut carbon emissions in line with international targets have come under renewed strain since the nuclear crisis in Japan led some countries to shelve plans to use the technology.

Switzerland became the latest country to decide to phase out nuclear power last week, citing concerns over the accident at the Fukushima plant that was left stricken by a 9.0 magnitude earthquake and tsunami in March.

The Swiss decision not to build any new nuclear stations – three were in the pipeline – follows similar announcements in Germany, Italy and further afield in Thailand and Malaysia, where governments have opted to freeze or forgo plans to build nuclear power stations.

The Swiss government said it would phase out nuclear power by 2034, a decision that requires the closure of five nuclear plants that provide 40% of the country's electricity. No plants will be phased out of use ahead of schedule, however. An estimated 20,000 people protested in Switzerland last weekend against nuclear power in the country.

To make up the shortfall, Switzerland will be forced to rely more on hydroelectric power, much of which it now exports as green energy to neighbouring countries, including Germany and Italy.

In Germany, Europe's largest economy and power market, seven nuclear power plants have been closed and plans to extend the running life of the remaining reactors have been put on hold pending the formation of a new energy policy due in July.

The International Energy Agency warned on Friday that Germany's moratorium on nuclear power will add 25m tonnes a year to the country's carbon dioxide emissions.

Plans to build nuclear power stations in earthquake-prone Italy have been halted, as have projects for five plants in Thailand. Malaysia, which had hoped to switch on its first nuclear station in 2021, will reconsider after reviewing the crisis at Fukushima.

Ruling out nuclear power will make countries more reliant on low-carbon alternatives, some of which have yet to prove themselves on an industrial scale, such as carbon capture and storage, which removes carbon dioxide gas from fossil fuel power stations.

"The decision you make by excluding a technology is that you have to rely on the others. It doesn't necessarily mean your energy system is more carbon intensive or more costly, but you have to replace that excluded technology with something else," said Jeff Hardy at the UK Energy Research Centre.

"Some of the alternatives, like burning fossil fuels with carbon capture and storage, are not yet proven at full scale, so if they don't deliver, or deliver late, that can affect your plans," he added.

In a report by government advisers last week, nuclear power was singled out as the cheapest way for the UK to grow a low-carbon energy supply, at least over the next decade.

The influential committee on climate change envisaged nuclear and renewable energy as having a 40% share each of the energy mix.