Tom Chivers is a science writer who has worked at BuzzFeed and the Daily Telegraph newspaper. The opinions in this article belong to the author.

(CNN) The world is heating up dangerously and the oceans may be dying. In this context, the UK's proposed plan to ban plastic straws feels a little like spitting in the wind.

No one knows exactly how many plastic straws the UK uses per year.

A figure put out by the Department for Environment, Food and Rural Affairs (DEFRA) suggested 8.5 billion -- that's about 130 for every man, woman and child in the country. The World Wildlife Fund claimed it was 42 billion straws, or 640 per person.

Both of these figures are hugely speculative , and both based on estimates (arrived at via different routes) from the research group Eunomia; the true figure may be half the DEFRA claim. Nonetheless, it is likely that the UK uses billions of straws every year, and that the majority of them are not recycled.

That's the backdrop to DEFRA's decision to launch a consultation on banning plastic straws, along with drink stirrers and cotton swabs. The UK's Environment Eecretary, Michael Gove, buoyed by the success of the levy of five pence on plastic shopping bags, said a ban could be in place within a year.

It sounds positive. But it's worth noting that, although "billions of plastic straws a year" sounds like a lot, it is a drop in the already plastic-filled oceans when it comes to plastic waste.

The World Economic Forum estimates that there are about 150 million tons of plastic in the world's seas.

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Doing something small is better than doing nothing, of course. And some activists argue that straws are a "gateway plastic ," and that banning them can be a step along the road to more stringent bans or levies, perhaps on drinks bottles. (Although there has also been a backlash from some people with disabilities, who say they need straws to be able to drink hands-free.)

Whether it's true or not, though, we're in danger of unearned self-congratulation. It's only two weeks since the release of the Intergovernmental Panel on Climate Change (IPCC)'s special report into the impacts of global warming, saying that drastic action is needed urgently to keep warming below 1.5°C to minimize the damage to human society.

It called for "rapid and far-reaching" changes to our energy production, our farming, our buildings and our transport. It added that we need to cut carbon emissions by almost half of 2010 levels by 2030. These are huge, epoch-defining changes to the way we live.

And that is only one way in which we are affecting the environment. The extent to which we are damaging the oceans' ability to regenerate themselves through overfishing, trawling and pollution is far from clear. But there are concerns that -- just as the collapse of bee colonies happened not just because of any single source of damage but from many different stresses pushing them beyond the point they could manage -- we could find ourselves at a point where the cycles of sea life suddenly break down.

Human-induced stresses have already led to a huge growth in the number of jellyfish, because the number of fish that compete with them and eat them has dropped so precipitously.

None of this is a reason not to ban plastic straws. But it's a reason to ban plastic straws as an afterthought, not to spend a year on a consultation.

Ban them without talking about it, and move onto a consultation about just how high our carbon tax ought to be -- how high is high enough to reduce emissions significantly, but low enough to stop a political revolt?

Ban plastic straws, but start talking about how to protect more of the sea from trawler fishing, or how to put the entire UK economy on a renewable-energy footing in a decade.

It's easy to make the perfect the enemy of the good. Banning plastic straws is probably better than nothing. But it's not very much better than nothing. We need bigger ideas than this, and fast.