Greenhouse gas emissions this year are likely to be higher than ever before, making targets to limit global warming by 2030 harder to achieve.
But there are ways to contribute, through lifestyle choices and actions to reduce your carbon footprint. Here, we calculate the costs and savings of these decisions.
Eating meat against veganism
A strict vegan diet that eliminates all animal products is difficult for many to digest. But a more flexible approach, such as eating more fish and reducing beef consumption, can further reduce the carbon footprint of your diet.
The meat and dairy industries are a serious contributor to global warming, accounting for around 14.5% of global greenhouse gas emissions, according to the Food and Agriculture Organization of the United Nations.
Cattle are the primary source of the livestock industry’s large carbon footprint. Cows spit methane, which has 80 times more warming potential as a greenhouse gas than carbon dioxide.
They also convert plant material into proteins with relative inefficiency. According to researchers from the University of Oxford and the LCA Research Group, for every 100g of protein from herd-raised beef, 50kg of CO2 equivalent is released during its production life cycle. This is almost nine times more than what is rejected by poultry and 25 times more than by tofu.
Eating less beef can also reduce human emissions. Consider that an average meat eater, consuming a varied daily diet of 2,000 calories, is responsible for 5.6 kg of CO2 per day (adjusted for age and sex), according to another Oxford study. Switching to fish can reduce that individual’s greenhouse gas emissions by 31% to 3.9 kg CO2, which is similar to switching to vegetarianism. But going vegan makes the biggest difference, cutting carbon output by about half at 2.9kg.
For those concerned with reducing their impact while enjoying the foods they love, the prescription is clear: lots of fruits and vegetables, with the occasional animal protein. It is good for the person and for the planet.
Fast fashion vs buy less
We all know that looking good has a price. But there is also a less visible cost borne by the planet. The global fashion industry is estimated to contribute up to 10% of carbon emissions, five times more than the entire aviation industry.
When choosing clothing, materials and workmanship are important. A polyester shirt, for example, has a carbon cost of 5.5 kg, about a quarter more than an equivalent cotton shirt. But the environmental cost of cotton remains high. About 2,700 liters of water and large amounts of pesticides are needed to make a single shirt. And locally produced polyester can reduce transportation emissions, whereas cotton production is mostly done in India and China and needs to be transported around the world.
However, the biggest carbon reductions have to come from the fashion industry itself, such as manufacturers switching to more environmentally friendly cotton-growing techniques. Recycling will also need to be prioritized more, since almost 90% of what the industry creates is landfilled or incinerated.
Shopping at retailers with strong environmental commitments can help. However, consumers are currently buying 60% more clothes today than 20 years ago. So choosing to buy fewer new clothes is the easiest thing to do. Less frequent washing, without a tumble dryer, will also reduce your carbon impact.
Holidays abroad vs stays
Holidays abroad have become easier on the wallet thanks to low cost airlines and package deals. But travel always leaves a heavy carbon footprint.
Let’s compare the impact of three holiday options for Britons: a Mediterranean cruise, a villa stay in Tuscany and a camping trip to Wales. Carbon levels are naturally lower for local trips, but it’s striking how low they are. The individual carbon footprint of cruising is almost five times that of a villa vacation and 25 times that of a camping trip.
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The nature of cruises means that even on a Mediterranean voyage with many stops, the ship needs power 80% of the time. Electricity for the extensive equipment on board must be generated by diesel engines while at sea.
Around 70% of the carbon generated by a holiday in a Tuscan villa comes from theft. Almost all of the additional carbon generated comes from renting a car during your stay.
The same is true for our camping trip to Wales where excluding car travel reduces emissions to around 1% of vacations in Tuscany.
The murky legal status of the open seas means that regulation to limit the environmental impact of shipping has been slow. Image-conscious cruise lines say they are ahead of the rest of the shipping industry with new ships powered by cleaner liquefied natural gas. However, these may even have a higher carbon footprint once gas leaks are taken into account.
Petrol vs electric cars
In December last year, more electric cars than diesel models were sold in Europe – for the first time. And, during 2022, global electric car sales are expected to top 6 million, according to consultancy Gartner.
Electric vehicles (EVs) are cleaner than their traditional counterparts. Consider the lifecycle CO2 emissions of all-electric cars produced in 2020, assuming they travel 250,000 km: in the UK, US and Germany, these vehicles offer significant emissions reductions by 76%, 60% and 49%, respectively, compared to gasoline-powered cars, based on the typical mix of energy sources in the power grid.
But the cleanliness of your electric car will actually depend on the cleanliness of the energy that powers it.
Germany’s underperformance in emissions reductions compared to the UK and the US reflects its reliance on coal as a fuel to generate electricity. Countries dependent on hydroelectricity, such as Norway, are doing much better. Britain gets more than a third of its electricity from renewables, so it’s relatively efficient too.
China is the world’s largest market for electric cars, with nearly 3 million cars sold last year. However, it is heavily dependent on coal-fired power, which means that a much smaller reduction in emissions for electric vehicle use occurs in the country, at less than one-fifth.
Cleaner electricity will eventually enable cleaner-running all-electric vehicles, with carbon savings from batteries compared to gasoline-powered cars increasing as power grids become greener.
Bitcoin versus Ethereum
Tesla’s claim to be working towards a zero-emissions future took a hit in 2021 when the electric car company opted to invest $1.5 billion in bitcoin.
Most cryptocurrencies, including bitcoin, are created by “mining”, which requires power-hungry computer processors. Private cryptocurrency investors are therefore financing climate change in the same way as if they were buying shares of oil majors.
Environmental costs are rising along with bitcoin prices, which have nearly doubled since the start of the year. The higher the price, the greater the demand for mining to put new coins into circulation. The more coins mined, the more complex the proof-of-work algorithm required to add blocks to the bitcoin blockchain. This, in turn, requires more processing power and electricity.
So, with nearly 19 million out of a possible 21 million bitcoins mined so far, normal computers are no longer able to do the job. And the share of renewable energy used for bitcoin mining has fallen from around two-fifths in 2020 to around a quarter now, says Alex de Vries, an economist who runs the blog Digiconomist. Bitcoin’s annual carbon footprint is now 114 million tons of carbon dioxide, equivalent to the carbon footprint of the entire Czech Republic. A single bitcoin transaction has the same carbon footprint as 2.8 million uses of a credit or debit card.
Plans have been announced to make rival blockchain Ethereum greener this year. A new underlying protocol, known as proof-of-stake, will use 99.9% less energy, it is claimed.