Lord Sacks was knighted in 2005 for services to interfaith relations
Europe is facing a population crisis because of attacks on religion by secular writers, Britain's chief rabbi has said.
Lord Sacks blamed Europe's falling birth rate on a culture of "consumerism and instant gratification".
He said the continent was "dying" and accused its citizens of not being prepared for parenthood's "sacrifices".
He made his comments in a lecture for Christian think tank Theos in central London on Wednesday.
The 61-year-old, who took his seat in the Lords last week, said: "Wherever you turn today - Jewish, Christian or Muslim - the more religious the community, the larger on average are their families.
"The major assault on religion today comes from the neo-Darwinians."
One of the leading "neo-Darwinians" is Richard Dawkins, whose bestseller The God Delusion argues the rise of religious fundamentalism has divided people around the world.
Lord Sacks said Europe was the most secular region in the world and the only continent seeing populations fall.
He said parenthood involved "massive sacrifices" of money, attention, time and emotional energy.
Lord Sacks asked: "In [modern Europe]... where will you find space for the concept of sacrifice for the sake of generations not born?"
He continued: "Europe is dying, exactly as Polybius said about ancient Greece in the third pre-Christian century.
"We are undergoing the moral equivalent of climate change and no-one is talking about it."
The chief rabbi was knighted in 2005 for services to the community and interfaith relations.
He has been chief rabbi of the United Hebrew Congregations of the Commonweath for 18 years.