The Shell scenario team worked with The Nature Conservancy (TNC) on this problem and again with MIT on the associated climate modeling. We used the recently developed TNC database of land use change options, which includes reforestation opportunities and other such programs, all mapped out against current global land use. Of these, reforestation offers by far the largest carbon sink. With this knowledge, we developed an addition to Sky that sees an area approaching the size of Brazil, or about 700 million hectares, being reforested over the coming decades.
This would utilize all the global reforestation options presented by TNC and provides an additional carbon sink of some 10Gt per year by 2070. Importantly, it also remains compatible with the other land use demands emerging from Sky, such as for biofuels and bio-energy with carbon capture and storage.
If social barriers can be overcome, such as the impact on agricultural communities, so-called “nature-based solutions” (NBS), such as reforestation, can help to limit peak warming because their scale-up can be considerably faster than the comparable transformation of energy technologies.