Biouhel byl poprvé v roce 2018 zahrnut mezi slibné emisně negativní technologie ve Zvláštní zprávě panelu IPCC. To znamená, že se biouhel stává prostředkem odstranění emisí uhlíku s označením PyCCS. Podrobné informace jsou v článku Biochar and PyCCS included as negative emission technology by the IPCC .

IPCC passages on biochar and PyCCS

In the 15th IPCC special report on Global Warming of 1.5 °C (http://www.ipcc.ch/report/sr15/), biochar and pyrogenic carbon capture and storage are, for the first time, cited and credited as promising negative emission technology. While in the Summary for Policymakers biochar is not explicitly mentioned, soil carbon sequestration was included:  

C3.1. Existing and potential CDR measures include afforestation and reforestation, land restoration and soil carbon sequestration, BECCS, direct air carbon capture and storage (DACCS),
enhanced weathering and ocean alkalinization. These differ widely in terms of maturity, potentials, costs, risks, co-benefits and trade-offs (high confidence). To date, only a few published pathways include CDR measures other than afforestation and BECCS. {2.3.4, 3.6.2, 4.3.2, 4.3.7}

In the extended report, biochar appears in the following sections: 

2.3.4.1 CDR technologies and deployment levels in 1.5°C-consistent pathways

Approaches under consideration include the enhancement of terrestrial and coastal carbon storage in plants and soils such as afforestation and reforestation (Canadell and Raupach, 2008), soil carbon enhancement (Paustian et al., 2016; Frank et al.,2017; Zomer et al., 2017), and other conservation, restoration, and management options for natural and managed land (Griscom et al., 2017) and coastal ecosystems (McLeod et al., 2011). Biochar sequestration (Smith, 2016; Werner et al., 2018; Woolf et al., 2010)provides an additional route for terrestrial carbon storage. Other approaches are concerned with storing atmospheric carbon dioxide in geological formations.

2.3.4.2 Sustainability implications of CDR deployment in 1.5°C-consistent pathways

There are also synergies between the various uses of land, which are not reflected in the depicted pathways. Trees can grow on agricultural land (Zomer et al., 2016) and harvested wood can be used with BECCS and pyrolysis systems (Werner et al., 2018). The pathways show a very substantial land demand for the two CDR measures combined, up to the magnitude of the current global cropland area.

4.3.7.3 Soil Carbon Sequestration and Biochar

[…]
Positive side effects include a favourable effect on nutrients and reduced N2O emissions(Cayuela et al., 2014; Kammann et al., 2017).