Bill Hare is CEO and founder of Climate Analytics, and Claudio Forner is head of climate policy at Climate Analytics.   

To address climate change, the answer should be relatively simple: governments need to decarbonise their economies by first focusing on stopping the burning of fossil fuels. But we are currently facing a crisis involving the land sector that could put the 1.5˚C warming limit at further risk.  

The scientific community is clear that including land and forest carbon storage together with fossil fuels and other emissions in national single national targets – as some governments are doing – will likely allow for greater emissions of fossil fuel carbon. This will hinder our ability to limit warming to 1.5°C, and in the worst case it may become impossible. We explain why in a recent report. 

Two examples illustrate the scale of this crisis. Australia and Brazil are relying on their reported land carbon sequestration to meet a substantial part of their 2030 and/or 2035 climate targets, significantly reducing the crucial cuts needed in fossil fuel-related carbon dioxide (CO₂) emissions.    

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Let’s be clear: the idea that land-based carbon removal/sequestration can “offset” CO₂ emissions from burning fossil fuels is scientifically flawed. For all practical purposes, fossil fuel CO₂ emissions are irreversible. They can stay in the atmosphere for thousands of years, whereas land-sector “offsets” or “sinks” are impermanent – especially when considering the increasing number of wildfires around the planet.   

And this is not the only issue: there’s a range of other substantial problems that have been analysed in the scientific literature. 

Under the Paris Agreement’s emissions reporting rules, governments are allowed to equate fossil fuel emissions and the drawdown of CO₂ by some natural carbon sinks – like the boreal forests – as a one-for-one trade, as set out in this recent paper published in Nature. This means a country could appear to have ‘achieved net zero’ while still contributing to ongoing warming, as emissions continue to rise amid increased tree planting and forest protection. 

Carbon fertilisation confuses the numbers

Many countries, particularly developed-country governments, are using ‘managed land’ definitions to claim that carbon uptake from their forests and other ecosystems is additional because of direct human activities, when much of it may be just passive carbon uptake due to atmospheric CO₂ fertilisation and other effects caused by fossil fuel emissions. For example, increased levels of CO₂ in the atmosphere lead to increased growth by plants and more carbon uptake – a phenomenon that is not the result of active forest management. 

One recent estimate is that about 44% of the additional carbon sequestered in the terrestrial ecosystem since the 2000s is due to the carbon fertilisation effect which, in turn, is mostly due to fossil fuel emissions. A substantial fraction of this would be counted within government accounting frameworks for their reporting of what’s called ” LULUCF” (Land Use, Land Use Change and Forestry).  

A clear example is Australia, which, in recent years, has continually revised both its historical and projected land sector emissions and in particular carbon sequestration, to the extent that it can now claim to have nearly reached its 2030 target, while barely taking any new action to cut fossil fuel emissions. 

In the case of Brazil, its 2035 NDC is cast in net emission terms and does not differentiate between the contribution of its land sector and the fossil fuel sector, making it impossible to work out what, if anything, is actually going to be done.  

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