Greta Thunberg and David Attenborough may be separated greatly by age and experience, but both have arguably done more in the past year than any others to re-awaken our concerns over climate change.

Transport, and the emissions it generates, is a major component of anthropogenic climate change, but it has seemed for a while that we had found the solution. Just switch to electric cars, something that the Irish Government wants us to do, wholesale, from 2030 onwards. It seems almost childishly simple - remove the emissions from everyone’s car, and bada-bing; climate crisis over.

Or will it be? There are some figures which should make for at least concerning reading, if not outright worry when it comes to electric cars, and one of those came from the company that made the first ever car - Mercedes-Benz. Launching its new EQC all-electric crossover this past week, Mercedes casually mentioned that after 200,000km of daily use, an electric car’s total well-to-wheel emissions will have fallen to 60 per cent of those of a petrol-engined car, or 30 per cent if all of the juice going into the batteries comes from renewable sources.

200,000km is a lot. That’s roughly ten years’s driving for most of us, which means that assuming you buy a new electric car tomorrow, it’ll be 2029 before you’ve reduced your notional petrol car emissions by one half. Along the way, many, many millions of batteries will have to have been created for all of the other electric cars we’re going to have to buy, which is in and of itself an issue that’s starting to cause concern.

Petrol option? There are some who think that a massive take up of electric cars may cause more harm in the short term than good. Mazda, for one, believes that petrol engines have a much more important role to play in saving the planet than commonly thought. I’ll wait a moment for that sentence to reach the ears of Elon Musk and for him to truly, comprehensively, throw his toys out of his battery-operated pram, but when you listen to what’s being said, Mazda may well have a serious point to make.

“We’re not electric vehicle deniers” Mazda UK’s Graeme Fudge told The Irish Times. “They’re the right way to go in terms of air quality. But with 84 per cent of vehicles still going to be powered by internal combustion, we need to clean that up.”

That 84 per cent number comes from the prediction that by 2035, in spite of the anticipated electric revolution, more than three quarters of our cars will still be primarily powered by internal combustion, even if an increasing percentage will use some form of hybrid battery assistance.

Generating energy Mazda’s argument, then, is that while it’s all well and good putting all hands to the pumps to drive forward electric propulsion, there are still significant gains to be made when it comes to combustion engines, especially petrol ones. Added to which is Mazda’s claim that, thanks to the fact that we still use large quantities of fossil fuels to generate our electricity, that an improved petrol engine can actually be cleaner, in a holistic sense, than a battery car plugging into the mains.

“Zero emission claims can be disingenuous when you look at well to wheel figures. A fossil fuel internal combustion engine produces as much Co2 if you look at well to wheel” said Fudge. “We believe that Co2 reduction isn’t just about battery, it’s about a whole suite of technology. Think of what we are doing as manufacturers on a global level. So, can you come up with something that’s both enjoyable and eco-friendly and ensure that everyone in society has unlimited mobility?”

Okay, so there’s a certain amount of ‘they-would-say-that-wouldn’t-they’ about Mazda’s claims of being able to match electric efficiency with a better petrol engine. The company is absent from both the electric and hybrid markets at the moment, and is playing catchup. Such a flashy headline as claiming that petrol engines are more efficient than battery motors is just the sort of attention-grabbing thing you might expect a car maker to do in such circumstances. So take an appropriate amount of salt with all of this.

What scientists say There’s also some science that disagrees with Mazda’s claims. The Union Of Concerned Scientists, nonprofit organisation founded 50 years ago by scientists and students at the Massachusetts Institute of Technology, studied the ‘well to wheel’ conundrum and came up with the following conclusion: “We found that battery electric cars generate half the emissions of the average comparable gasoline car, even when pollution from battery manufacturing is accounted for” said the UCS.

For larger, longer-range EVs that travel more than 250 miles per charge, the manufacturing emissions can be as much as 68 per cent higher. The Union’s findings were that: “Manufacturing a midsized electric vehicle (EV) with an 84-mile range results in about 15 per cent more emissions than manufacturing an equivalent gasoline vehicle. For larger, longer-range EVs that travel more than 250 miles per charge, the manufacturing emissions can be as much as 68 per cent higher.

"These differences change as soon as the cars are driven. EVs are powered by electricity, which is generally a cleaner energy source than gasoline. Battery electric cars make up for their higher manufacturing emissions within eighteen months of driving - shorter range models can offset the extra emissions within 6 months - and continue to outperform gasoline cars until the end of their lives.”

According to the UCS, even US states such as Virginia, which gets almost all of its electricity from burning coal, would see a reduction in overall emissions if people switched to electric cars. In Ireland, with our current mix of fossil fuel and renewable energy production, an electric car charging from the national grid has effective Co2 emissions of around 70g/km, according to the ESB.

There are other worries. Amnesty International has been raising concerns, for the past few years, about the potential for human rights abuses in the mining industry from which we get the precious metals needed to build EV batteries. Then there are worries that recent licences issued for deep-sea mining for minerals such as cobalt (a mineral needed for high-tech lithium-ion batteries) could disturb, even destroy, delicate underwater habitats.