A leading evangelical Church of England bishop and a Labour member of the House of Lords have criticised the Pope's encyclical on the environment as a "naive" document that hankers for a lost world.

The Bishop of Chester Dr Peter Forster and Labour peer Bernard Donoghue, a lay Catholic, say Pope Francis' landmark document Laudato Si betrays an idealism that longs for a world where cats no longer chase mice and species do not kill and eat each other or become extinct.

The Pope said in the encyclical that the world risked becoming "an immense pile of filth" and that doomsday predictions about its future can no longer be met with irony or disdain.

Dr Forster and Lord Donoghue challenge this pessimistic view.

"To us the encyclical is coloured too much by a hankering for a past world, prior to the Industrial Revolution, which is assumed to have been generally simpler, cleaner, and happier. There is little historical evidence for such a vision, and for most people then life was brief, painful, poor, and even brutal," they say in a paper for the Global Warming Policy Foundation.

In particular, they criticise the encyclical for its negative view of capitalism.

They write: "Markets are the lifeblood of wealth creation, and wealth creation is the necessary, if not sufficient, prerequisite to the lasting alleviation of poverty."

Confessing that they share the Pope's deep desire to reduce poverty in our world and that the costs should fall more on the richer nations and the rich within nations, than on those who are poor, they argue nonetheless that "the energy policies advocated in the encyclical are more likely to hinder than to advance this great cause."

They agree that responsible stewardship is needed. But they also warn against a "romantically myopic" view of the impact of humans on the environment.

Spelling out the realities of day-to-day life on the environment, they continue: "Every time a road or house is built, countless numbers of insects and animals are killed or displaced. The same is true when we spray our garden plants, or crops, with pesticide.

"Each time we cut our lawn, thousands of small insects are likely to be killed."

To imagine that human civilisation can develop without impact on the natural world would be a "misleading idealism", they argue, suggesting the encyclical could have been more open about these realities.

They also challenge any assumption that higher carbon dioxide in the atmosphere is a bad thing, and point out instead that it is essential to support life. "The human body is not adversely affected by higher carbon dioxide levels, as is evidenced by submarines, which typically operate with levels about 400 per cent higher than in the atmosphere. We sympathise with much of what the Pope says about waste and pollution, but this has little to do with carbon dioxide."

Finally, they confront the difficult question of population growth. "The world's population is expected to exceed 10 billion later this century. Ironically, the most likely way to avoid this would be to have precisely the worldwide economic growth against which the Pope warns, as there is plenty of evidence that as a country's wealth increases, its birth-rate typically falls."

The critique was welcomed by the influential Archbishop Cranmer blog, which stated: "The Forster-Donoughue thesis is measured, intelligent and polite as it interrogates the pontifications and probes the pious platitudes of the encyclical's unscientific generalisations, ahistorical assertions and economic banality."

Australia's Cardinal George Pell also sounded a note of caution. Speaking to the Financial Times, he said the encyclical has many interesting elements and parts of it are beautiful. "But the church has no particular expertise in science. The church has got no mandate from the Lord to pronounce on scientific matters. We believe in the autonomy of science."