As shoppers dusted off their credit cards in anticipation of juicy Black Friday discounts this week, one study calculated their online purchases could release about 386,243 tonnes of carbon emissions, mainly from parcel deliveries.

That is equal to more than 215 flights taken between London and Sydney in just 24 hours, and roughly the same weight as 3,679 blue whales, said the report from money.co.uk, a UK-based personal finance website.

The amount of online Black Friday purchases and associated carbon emissions are expected to be about 10% lower this year than during the peak pandemic lockdown period in 2020. But annual spending on Black Friday, while cheaper for consumers, comes with a significant cost to the planet, analysts say.

This is clearly at odds with the rising trend of stronger action to curb climate change. A separate report this week from the Net Zero Tracker initiative found net-zero emissions goals set by national governments now cover 90% of global gross domestic product and 88% of emissions.

A growing number of companies and cities have also now set net-zero emissions targets for the coming decades - we take a closer look at the trend and its importance for the Earth's climate:

WHY DOES 'NET ZERO' MATTER?

It may be the latest buzzword in the world of climate action but it's key to keeping us safe from harm, scientists say.

The U.N. climate science panel has said man-made carbon dioxide emissions need to fall by about 45% by 2030, from 2010 levels, and reach "net zero" by mid-century to give the world a good chance of limiting warming to 1.5C and avoiding the worst impacts of climate change.

Under the 2015 Paris Agreement, nearly 200 countries said they would act to limit the rise in global average temperatures to "well below" 2 degrees Celsius above pre-industrial times and strive to keep it to a ceiling of 1.5C.

But the world has already heated up by about 1.1C and is on track for warming of close to 2.5C this century, if current pledges to rein in still-rising emissions by 2030 are implemented, researchers estimate.

Scientists say that would bring ever-worsening extreme weather and potentially catastrophic sea level rise, making some parts of the planet uninhabitable and fuelling hunger and migration.

These risks - and mounting public pressure - are why a fast-increasing number of countries, companies and others are promising to cut their planet-warming emissions to net zero by 2050 or soon after.

If the mid-century net-zero goals set so far are actually met, global warming could be kept to about 1.8C, analysts say.

Some climate activists have criticised 2050 net-zero goals for enabling countries and companies to postpone emissions reductions until a vague later date.

WHAT IS NET ZERO?

Achieving net-zero emissions isn't the same as eliminating all emissions.

It means ensuring any human-produced carbon dioxide or other planet-warming gases that can't be avoided or locked up are removed from the atmosphere some other way.

This can be done naturally, such as by restoring forests that suck CO2 out of the air. It can also be done using technology that captures and stores emissions from power plants and factories or directly pulls CO2 from the atmosphere.

Planting more trees worldwide is a popular way to absorb and store more carbon, but human-made technologies that perform the same job remain expensive and have yet to be deployed on a large-scale.

Scientists say carbon "removals", in any form, cannot substitute for cutting greenhouse gas emissions as fast as possible.

There has been a lot of debate around carbon offsetting - where governments, companies or individuals pay for emissions to be reduced or avoided by clean energy and nature conservation projects elsewhere, and then count those reductions as part of their own carbon-cutting efforts.

PM

00 : 01 / 05 : 47YO

WHO HAS COMMITTED TO NET ZERO?

According to analysis released in November by the Net Zero Tracker, national net-zero emissions goals now cover 90% of global gross domestic product, 88% of emissions and 85% of the world's population.

The global initiative - led by the Energy & Climate Intelligence Unit, Data-Driven EnviroLab, NewClimate Institute and Oxford University’s Net Zero Initiative - also said the total revenue covered by the net zero targets of publicly traded companies amounts to just over $19.5 trillion.

Corporations tend to set targets that lack the rigour needed to deliver a timely, effective arrival at net zero but, as more commitments are adopted, their integrity is slowly improving, it added.

Among countries, two tiny developing nations, Suriname and Bhutan, have already achieved net-zero emissions, through measures such as restoring or planting forests and adopting renewable energy, while Panama is also expected to be certified later this year.

Of the 136 with net-zero targets, countries covering only about 10% of global emissions - including Denmark, France, New Zealand, Britain and Spain - have enshrined them in law, while a further 43% have included the goal in a policy document.

Countries accounting for about 45% of global emissions aim to achieve net zero by 2050, with others responsible for 55% having later targets.

HOW DO YOU SET A NET ZERO TARGET?

The World Resources Institute (WRI) and the 2050 Pathways Platform - which work with governments and others on their climate commitments - say cutting emissions within national boundaries should be the first priority, with efforts to offset what remains only considered after that.

Right now, countries vary in whether their net-zero targets include offsetting emissions internationally, such as by paying to protect forests in the Amazon.

Net Zero Tracker says 91% of country targets, 79% of city targets, 78% of regional targets and 48% of public company targets fail to specify if - and how - offsets will be used in net zero plans.

To be credible, net-zero targets should cover all greenhouse gases, including methane, and all economic sectors, as well as international aviation and shipping, WRI says.

Those trying to achieve net-zero emissions should do so by 2050 or earlier, with the highest-emitting countries doing the most, fastest, while plans should be crafted in consultation with those they will affect and clearly communicated, WRI said.

When it comes to companies, net-zero targets vary widely in terms of which parts of supply chains - and sources of emissions - they cover, and are difficult to compare, says the Science Based Targets initiative (SBTi), which has released guidelines to help remedy that.

In an October report, consultancy firm Accenture found that, of the largest 1,000 listed companies across Europe’s major stock indexes, one-third had pledged to reach net-zero by 2050.

But of these, just 5% are on track to achieve their net-zero target if they continue the pace of emissions reduction from the last decade, and only 9% are on course to meet their goal by 2050.

IS NET ZERO AN EXCUSE TO KICK ACTION DOWN THE ROAD?

The "Race to Zero", launched on World Environment Day in June 2020, brings together businesses, cities and other organisations that aim by around mid-century to cut their planet-heating emissions to net zero.

With a growing focus on the robustness of net-zero commitments, Race to Zero members must all meet stringent criteria, including submitting a plan in line with climate science and setting interim targets to reduce emissions.

About 43% of the world’s 632 largest public companies by revenue plan to use carbon offsetting, according to Net Zero Tracker - but 66% of those plans fail to specify conditions on the use of offset credits. Ten percent of companies have committed to avoid using any offsetting whatsoever.

The steps needed to get to net zero must be incorporated now into ambitious 2030 emissions reduction targets in national plans and reflected in day-to-day decision-making, to avoid investments going into high-carbon technologies or infrastructure, according to WRI researcher Kelly Levin.

Meanwhile, the International Energy Agency released a long-awaited roadmap in May showing how the world's energy sector can slash its planet-heating emissions to net zero by 2050, which it says would give the best chance of limiting global warming to 1.5C.

The agency said reaching net-zero emissions by mid-century was possible but the pathway to get there was "narrow and requires immediate action across all countries to begin an unprecedented transformation of how energy is produced, transported and used worldwide".

This explainer was updated on Nov. 26, 2021, with information from the latest analysis by Net Zero Tracker, a global initiative led by the Energy & Climate Intelligence Unit, Data-Driven EnviroLab, NewClimate Institute and Oxford University’s Net Zero Initiative .

‍