Global warming could contribute to a rat population explosion with potentially disastrous human health consequences, an expert warned today.
Milder winters and hotter springs were already increasing the rat population significantly, he said.
And Oliver Madge, chief executive of the British Pest Control Association, warned the chances of rodents invading people’s homes increased greatly as a result, with sudden outbreaks of disease far more likely.
He also claimed controversial fortnightly rubbish collections was a “bandwagon” for people to blame local authorities for rises in rodent infestation.
Mr Madge said: “As an industry we are still compiling the hard stats but the early indications are that the weather changes are having a massive impact on the rat population.
“The problem is that it used to be that when we had cold weather in the winter, a natural percentage of the rat population was killed off by the temperatures.But now, with milder winters.
“The problem is doubled when you get hot springs like this year too, because not only are rats all surviving winter, but the lowest temperature they can reproduce at – around 12 to 14 C – are coming much earlier and so mating seasons start earlier and last longer.”
He said that essentially meant there were more rats with more time to reproduce, adding: “This is a very worrying time when it comes to rats and I think there is the potential for a rat population explosion.
“The weather is not the only factor that helps rats survive, but it’s the only one we can’t do anything about.”
Rats are prolific disease-carriers, able to transport around 30 that are dangerous to humans.
Mr Madge said: “If we get a population explosion, then there is far more chance of diseases like Weils disease in rural areas or salmonella in urban areas being passed from rats to humans.”
He said that there were other problems causing worry over rodent control.
He said: “There will always be rats and they will always bring problems. But though we can’t do something about the weather, we have got to attack the other three criteria rats need to survive – food, water and habitat.
“Actually one of the major problems as well as the weather is the fact there are more food sources now – there is much more junk food in circulation, particularly in towns and cities.
“In addition to that, some rats are now becoming immune to some of the rodenticides on the market at the moment – so it looks as though we’re going to have more rats and less products to control them.
“And even people trying to be greener doesn’t always help – things like building up compost heaps with food in can be a perfect environment for rats to survive in.
“But also we are not as good at sewer-bating any more – at actually killing off the rats in the habitats they survive in best.”
But he said fortnightly waste collection – brought in by some local councils – were not a major problem, if people organised their rubbish properly.
He added: “Fortnightly collections are just a bandwagon that people jump on so they can blame their council if rats become a problem. But it’s just pointing fingers really.
“If people use wheel bins and look after their waste build-ups properly, then they can avoid at least rubbish collection causing a problem.”