MARK Smith ("Traffic, not ice, is the real problem for this bridge", The Herald, February 14) is correct in asking for more public transport, but only partly correct. I remember watching the Open University analysing the Bay Area Rapid Transit (BART) system some 40 years ago, planning, design, and implementation. BART is a success but there is still a huge river of vehicles travelling through California, which no transit system could possibly cope with.#

There is the problem. Density of population allows for the mass transit of some people, but much of Scotland is sparse and remote from any point of departure. At the time the programme on BART was being screened, many people in Scotland had works buses to take them to the pit, factory or engineering works; there are few big employers now, so that no longer applies.

We should concentrate on utilising green fuels: battery or hydrogen, because car travel will still be required. Scotland is ideally placed to produce hydrogen, if green producers were denied payment for downtime, and had instead to utilise their excess power to make hydrogen. Car parking should be costly (with an end to Unionist hypocrisy on this) to encourage car sharing, and vehicle taxation dependent on its green credentials.

GR Weir, Ochiltree.

REGARDLESS of whether there is any scientific merit in the theory of global warming, the remarkable thing is that the British Government is making no positive effort to prepare for the elimination of fossil fuels from our economy. Certainly, ministers have announced when new conventional cars and hybrids will be banned – somewhere between 2032 and 2035. Also, the Scottish Government has helpfully invited councils to set up low emission zones.

However, where is the preparatory work for massively increasing our generating capacity? We currently generate around 335 TWh (TeraWatt hours) of electricity each year. To replace all petrol and diesel cars and lighter commercial vehicles would need around a further 375 TWh. Add in lorries and other larger commercial vehicles and a further 100 TWh would be required.

A further 510 TWh would be needed annually to replace all domestic oil and gas heating and cooking. In other words, we will need to more than triple electrical generation and that is before we consider industrial users of energy from fossil fuels.

The only plausible carbon-neutral source of that amount of electrical power for the UK is nuclear power. Wind turbines cannot provide the baseload because their output is wildly variable, and because there is no economic method of storing large amounts of electrical power. And yet we are not starting the process of commissioning dozens of new nuclear power stations.

Also, a kiloWatt hour of electricity currently costs around four times as much as a kiloWatt hour of energy from mains gas. This means that switching over to electrical heating will push many millions into fuel poverty, even ignoring the fact that increasing demand and inadequate supply will push up the price of electrical power much further.

Furthermore, there is currently no viable alternative to plastics derived from the oil and gas industry. For a great many purposes, including for example electrical insulation and medical uses, they simply cannot be cut out.

The approach of Westminster, of Holyrood and of the climate change activists is a recklessly dangerous fantasy.

Otto Inglis, Edinburgh EH4.

THE problem with letters such as from Dr Craig Dalzell (February 12) is that there is no figures detailing the costs of such a project other than "this will cost a fair amount". Well, if it cost £7 million to lay 10 miles of tram lines in Edinburgh, what will be the price tag to dig up every road in Scotland from Muckle Flugga to the Mull of Galloway?

The CEO of ScottishPower has already pointed out at the World Forum on Climate Justice that renewable energy is too expensive, hence he recommended to MSPs that the financial burden should be passed to the taxpayer. In addition, if Japan, the third-largest economy, plans to emulate Germany by building 22 coal-fired power stations as its economy cannot afford the cost of renewable energy, why does the UN not postpone COP26 until China, Russia, India and Brazil agree to reduce their emissions even if those of Japan and Germany would increase ?

Ian Moir, Castle Douglas.