At Microsoft, at BP and Shell, and at airlines such as KLM and easyJet, they will have looked at the many forest fires with some concern this summer. These companies – like many others – pay for the construction or maintenance of forests in order to compensate for their own greenhouse gas emissions. For every tonne of carbon dioxide captured in trees, the company receives an emissions certificate. The trade in these certificates is now a multi-billion dollar business. It’s also a smart idea. Trees absorb CO2 , grow from the carbon and release the oxygen again. A company that plants trees, or creates entire forests, helps to reduce the amount of CO 2 in the atmosphere and can then deduct it from its own emissions. Win-win, it seems: more nature and less greenhouse gases, while companies meet their environmental obligations in an affordable way, while also polishing their ‘green’ image. But what happens if such a compensation forest goes up in flames, so that all stored CO 2 ends up in the atmosphere again? Shouldn’t the company then still enter the released CO 2 in its own carbon accounting? This is one of the reasons why critics reject such a compensation system. The CO 2 emitted by companies remains in the atmosphere for centuries, they say. In order to really compensate for these emissions, the compensation forests would therefore have to be maintained over many generations. But trees are sometimes cut down (legally or illegally), they can get sick and when they die, the CO 2 is slowly released again. And a forest fire can wipe out all climate gains in one fell swoop. Additional greenhouse gases The figures show that a forest fire does not involve small amounts of CO2 . The European Union’s Copernicus Atmosphere Monitoring Service (CAMS) calculated that fires in the Northern Hemisphere released as much as 1.76 gigatons of carbon dioxide in 2021. That is more than double the CO 2 emissions of the whole of Germany. Forest fires in Europe were again responsible for many additional greenhouse gases this year. Precise figures are not yet available, but according to CAMS it is certain that emissions from forest fires this summer were the highest in the last 15 years due to the many fires in Spain, Portugal and southwestern France. Emissions from forest fires this summer were the highest in the last 15 years The US space center NASA , which collects a lot of atmospheric data using satellites, concluded that California wildfires had emitted more than 90 million tons of CO 2 by 2020. That is 50 percent more than the CO 2 emissions of the entire energy sector in California. “Forest fires create carbon emissions that affect the climate and trigger events that in turn contribute to even more wildfires,” NASA writes. Firefighters on their way to extinguish the so-called Bootleg Fire in July 2021. Photo Nathan Howard/AP Photo California, where emissions trading with the help of forest certificates has really taken off, has found a solution. Forestry companies that sell emission certificates must maintain a buffer of trees whose stored CO 2 they are not allowed to trade. This is 2 to 4 percent in case a forest goes up in flames. Trees must also be kept in reserve for possible insect pests and other tree diseases, as well as for the consequences of drought or storms (together about 6 percent). In addition, 9 percent of the recorded emissions may not be sold to absorb ‘human risks’, such as the bankruptcy of the forestry company or (illegal) logging. All in all, the forestry companies have to keep a ‘piggy bank’ of about 20 percent. So they have to keep one of every five trees they plant in reserve in case one of the other four dies. The buyers of the forest certificates are therefore not directly responsible for the extent to which they really reflect the amount of CO2 saved. Still, a company like Microsoft is very concerned about the forest fires. Not only will the price of the certificates rise sharply if the fire risk due to climate change increases further, it could also affect confidence in emissions trading and thus in the green ambitions of companies. Elizabeth Willmott, project manager of Microsoft’s carbon offsetting program, therefore argued at a 2021 meeting on emissions trading for a better assessment of the risks of this way of offsetting. At the time of Willmott’s plea, some of Microsoft’s recorded emissions literally went up in smoke. The infamous Bootleg Fire , a massive wildfire in Klamath Falls, Oregon, also hit the forests in which Microsoft had invested millions. “We don’t want this to force us to withdraw from nature-based solutions,” Willmott said. Net-zero EasyJet discontinues compensation Airline easyJet will stop compensating for the emissions caused by the company at the end of the year. Over the past three years, £25 million has been spent annually on buying off its emissions. In 2019 it was already said that this was a temporary program. The program has been criticized from the start, with double counting and unclear calculations of avoided emissions. EasyJet says it wants to spend the money that is now released on a plan for ‘net-zero’ emissions from 2050. To this end, the company wants to invest in more efficient aircraft and research into hydrogen-powered aircraft. The aim is to reduce emissions per passenger by 35 percent by 2035. Promise of climate neutrality For Microsoft, which has already spent more than a billion dollars on climate compensation, the forestry program is vital to fulfill the promise of climate neutrality by 2050. Microsoft is committed to neutrality across the entire value chain of its products, including consumer use and even its own past emissions. According to the tech giant, this involves a total of approximately 1.3 million tons of CO 2 . Without trees, that amount is unattainable for the time being. The question is whether the forest certificates are sustainable in the long term. It is certain that the current tree buffers linked to those certificates are insufficient. According to CarbonPlan, an organization that studies emissions trading and forestry projects, California’s reserves are rated for a maximum of one extreme fire season every four years — while two of the last three seasons qualify as extreme. According to a recent scientific study , a fifth of the buffer stock has already been exhausted in the past ten years. That is an amount that was actually intended for a whole century. A version of this article also appeared in the newspaper of October 4, 2022