The Conservative chairman of parliament's cross-party energy and climate change committee is to warn the government against reducing spending on low-carbon technology, saying it would be like "cutting the budget for Spitfires in 1939".

Tim Yeo, who was an environment minister in John Major's government, says his committee is speaking out on behalf of environmentalists, who are "holding [their] breath" after indications that the government will slim down commitments to sustainable technology when it announces new four-year spending plans for Whitehall departments in the comprehensive spending review on October 20. At a recent appearance in front of Yeo's committee, Chris Huhne, the climate change secretary, said "nothing was safe" in his department.

Yeo says he is concerned that upfront funding for clean coal technology will be delayed or worse; money for an upgrade of north-eastern ports needed for the establishment of large windfarms is unlikely to be secured; the Carbon Trust and the Energy Saving Trust will be scrapped; and funding for feed-in tariffs and renewable heat incentives will be reduced. If there is the slightest change to these mechanisms, Yeo says, the UK's renewables sector will become too unpredictable to survive.

Instead, Yeo tells the Guardian the government should be looking to increase spending, comparing the task with that during the second world war, when "the UK was running an even bigger deficit, but we would never have won the battle of Britain if spending on defence had been sacrificed".

Yeo uses statistics provided by the House of Commons library to show that despite the national debt, spending on defence went up by 125% between 1930 and 1939. He says that in many ways the "destabilisation" of the global climate poses as grave a threat. Cutting investment in green infrastructure would be "a folly, and something of a false economy".

The MP suggests there are other departments whose budgets should be plundered to safeguard the Department of Energy and Climate Change (Decc). David Cameron has ordered no detail of spending settlements to emerge before the spending review, but Yeo is concerned that since the deal struck by Decc excludes "nuclear and coal legacy costs" – as much as 40% of the department's budget – Huhne has had to find savings of up to a third elsewhere.

Last week it was reported that plans to build three new factories to make thousands of giant offshore wind turbines were in jeopardy because of uncertainty over port improvements. Officials at Decc were reported to be fighting to put up half the £60m they are required to do. But it has been reported they are struggling to secure the support of the Department for Business, Innovation and Skills in putting up the other half. Officials say the great prize for environmentalists is the establishment of a green investment bank, as advocated by Huhne, which would divert public funds to ensure that renewable and low-carbon schemes, such as the ports, have sufficient capital. This is unlikely to be ready to be announced in the CSR but though it is intended to assuage the green community, environmentalists want to see between £2bn and £6bn in public money behind it – more than simply an agglomeration of existing renewables funds – and it to be given an ability to borrow and lend.

Huhne settled his spending commitments on 30 September but officials believe the early settlement may have been cosmetic – driven by the Treasury's desire to have Huhne, who is a Lib Dem, and a trained economist, serving on the star chamber scrutinising the settlement proposals of other departments, including that of his fellow Lib Dem Vince Cable, whose business department is one of the largest non-ringfenced departments. Yeo urges Huhne to unofficially reopen his budget settlement at the end of the process and argue for a funding increase, not decrease.

He said: "Cutting spending on low carbon technologies now, would be like cutting the budget for Spitfires in 1939. The UK was running an even bigger deficit in the 1930s, but we would never have won the battle of Britain if spending on defence had been sacrificed. Of course, today we are not faced with imminent invasion, but in many ways the destabilisation of the global climate also poses a grave threat to our long term national security. In future, climate change could jeopardise our food security, cause unprecedented mass migration and conceivably even spark wars. It would be folly, and something of a false economy, to cut investment on green infrastructure now."

He calls for greater investment in green technology not less and adduces figures for the 1930s and the level of defence spending.

Yeo also quotes the words of foreign secretary William Hague to the Conservative party conference last week, when Hague said: "The scientific consensus on climate change tells us that it could give rise to the wars of the future. Even for those out there who might be sceptical, this is too great a risk not to act."