Net zero has become a buzz word in climate circles. Norway, Finland, Denmark, Iceland, Costa Rica, Chile, Fiji and the Marshall Islands have published the aim. France, Sweden and the UK have gone one further by writing it into law. But what does it mean? And why does it matter?

    The UN climate science body1 note that for the highest ambition goal of the Paris Agreement, namely to limit temperature rises to 1.5°C, the world needs to achieve net zero emissions by 2050. This means that the emission sources from human activities contributing to the build-up of CO2 in the atmosphere must be offset by sinks that absorb or capture the carbon. The net impact from humans on atmospheric CO2 needs to be neutral, in other words, net zero.

    The net zero concept matters because it is a straightforward way to measure progress on keeping temperature rises under control. If emissions are going up while carbon sinks are going down, the net zero outcome will take longer, and the planet will get hotter. This is the situation the world is in right now. In 2018 emissions from energy increased by 1.7 per cent from 2017, reaching a historic high of 33.1 Gt CO2.2 Meanwhile, between 1990 and 2015 the world’s forest area, a key natural carbon sink, decreased from 31.6 per cent of the global land area to 30.6 per cent according to the food and agriculture organisation. In 2018 alone, forest cover across the tropics decreased by 12 million hectares, an area roughly half the size of the UK3. Globally, June 2019 was the hottest June since records began in 1880, and nine out of the ten warmest Junes have occurred since 20104.

    A key advantage with the net zero concept is that it can be applied at different levels. For countries, it means taking an economy wide approach. The UK for example is considering how to address emissions across housing, industry, road transport, agriculture, aviation and shipping5. In addition, companies can adopt a net zero approach by becoming as carbon efficient as possible in electricity use and other processes, and address any remaining carbon exposure by helping to preserve carbon sinks. Industry reports, such as the Mission Possible series from the Energy Transitions Commission, provide roadmaps for sectors where there are technological difficulties. In the future as data improves it will be easier for individuals to see how they can get to a net zero lifestyle.

    There is still some way to go before a net zero narrative is embedded in business as usual conversations. Data availability remains a barrier for measuring progress. Identifying a viable net zero plan is also a challenge, since countries have to work with various economic starting points and industrial structures. More than that however, is that much focus has, rightly, related to reducing emissions in the energy system. This work must continue, but there is also an increasing urgency to retain and replenish natural carbon sink systems that support planetary health.

    The annual climate talks will take place in Chile in December6. Raising ambition on emission reduction will likely feature heavily throughout. Regional action weeks taking place in Brazil (Salvador da Bahia, 19th August), Thailand (Bangkok, 2 September), and the United States (New York, 23 September) are designed to showcase country and corporate success and support new ambition. Finance is a key enabler for change. The race is on to deliver a net zero economy.

    1 Special Report on the impacts of global warming above 1.5°C – October 2018, Intergovernmental Panel on Climate Change
    2Global Energy & CO2 Status Report 2018 – March 2019, International Energy Agency
    3 World Resources Institute
    4 Global Climate Report – June 2019, National Oceanic and Atmospheric Administration
    5 Net Zero, The UK’s contribution to stopping global warming – May 2019, Committee on Climate Change
    6 The 25th Conference of the Parties to the UN Convention on Climate Change (COP 25)