Save the Earth from the sofa

Don't print on paper. Wash clothes in cold water. Hang them to dry. Unplug appliances at night — phone charger, television, kettle. But not the freezer, keep that on and filled to the brim. Switch off lightbulbs when you leave a room. No, wait — replace them with LED lights, and then switch them off. Then leave the room.

In fact, leave the house altogether, and downsize to an off-grid eco-farm in the Andes. Or just live in your garden shed. It's built from sustainably-sourced timber, right?

It's easy to feel overwhelmed when confronted with a list of Ways You Should Be Living Better. Humans are failing to make much of the required headway in the fight against climate change, and a deluge of well-intentioned but seemingly futile advice can dampen morale.

That's because the impacts of most eco-living suggestions — from emailing Christmas cards to starting a compost heap — amount to mere miniscule droplets in our rapidly warming oceans. Fussing over a thousand tiny changes might make a small puddle, perhaps — but is it worth the stress?

For armchair activists among the environmentally-inclined, it often feels there is just too much to do. Time is short, and habits difficult to change. Advice flips and flops: who even knows now whether dishwashers are more wasteful than hand-washing?

But now, let the loungers rejoice! Sometimes, the biggest impact comes from the smallest of actions. If you had to make, say, five changes in 2018 to help save the planet — what's the most you could do for the least effort?

Pig out

No, really. Eat more, if you want; just buy less. Although agriculture accounts for a quarter of greenhouse gas emissions, about a third of all food grown on this planet never actually gets eaten.

Of course, not all of this goes into the waste bin — the European Parliament reckons about half of EU food waste takes place at home — but it's still a simple starting point. The footprint of food waste amounts to a whopping 3.3 billion metric tons of carbon dioxide (CO2), according to the United Nations, making it amount to more than India's annual emissions.

But give up meat

And, on the subject of shopping baskets — swap steaks for veggies. Researchers at the University of Lund, who published a study this year on the most effective actions an individual can take to cut their emissions, estimate the switch to meat-free diets eliminates 820 kilograms of CO2-equivalent per person each year. This saves more than hanging clothes to dry them, upgrading lightbulbs and recycling combined.

So don't fret if you can't trace every item of tonight's dinner through the supply chain from field to supermarket shelf. Just make your meal out of plants — and remember to finish your plate.

Keep your feet on the ground

There are plenty of reasons to avoid flying. Hours in airport queues, endless security and passport checks, the inevitable morbid thought of "when did I last call home?" once turbulence kicks in during a thunderstorm. Sometimes the most relaxing breaks are not far-flung holidays but those spent sitting on the sofa with a cup of tea and a good book.

There is, however, also an environmental reason: flying is damaging for the planet. Not just because its emissions, per kilometer, are greater than those of cars or trains — but because budget flights also let us travel further than we ever feasibly could in the past. This has built an appetite for foreign getaways that is hard to break.

Cut out a single round-trip and you could save from 700 to 2,800 kilograms of CO2, depending on the distance traveled, fuel efficiency of the aircraft and weather conditions.

Put that into perspective: according to Eurostat, the average European emits about 900 kilograms of CO2 per year. You'd be hard-pressed to find a lifestyle change that effective, achievable without ever leaving the house.

Ditch the car

Well, maybe there is one. Don't drive. This seems strange to include in a lazy person's guide to saving the planet — what requires less energy than driving? — but bear with us on the logic here.

We know cars are bad for the planet. The average automobile spews out about 4,700 kilograms of CO2 per year, according to the United States Environmental Protection Agency.

But as well as being polluting, cars are also pricey.

You pay for the vehicle, the fuel, the taxes, the health care that comes from increased risk of all those cardiovascular diseases, the new car you have to get once the old one breaks down — don't forget insurance — not to mention driving lessons, parking and so on.

According to analysis by CJ Pony Parts, a car retailer, a bachelor degree-educated American spends an estimated 10 percent of his or her income on automobiles.

Think about all the hours spent slogging away to make up that hard-earned cash, and hopping on the bus suddenly seems an awful lot less effort.

Use protection

Kids are hard work. But the labor cost of popping to the shop to buy contraception is a lot less than that of raising a family — and the environmental cost of children.

It's difficult to put a number on how much CO2 a child adds to your climate balance — would you count the emissions of your children's children, or all their descendants? Most studies, however, agree it blows all other factors out of the water. The authors of the Lund University study put it at somewhere between 23 and 100 metric tons of CO2 per year.

Of course, having no children is hardly a solution to the threat of climate change in the sense that both could wipe out humanity. But how many children we have, and in which parts of the world, is worth considering.

A 2009 study from Oregon State University found that the "carbon legacy" of having one extra child was about 100 times greater in the US than in Bangladesh. This is largely because overconsumption, rather than overpopulation, is a primary factor behind climate change.

That means: for Westerners looking for low-effort activities to offset emissions, don't worry about the beeswax candles and organic wine. Focus on family planning instead.

Romance is too much work anyway, isn't it?