The forest-construction pump: how the building sector can become a carbon sink

From the biggest climate offender to a climate hero

Schellnhuber is the founding director of the Potsdam Institute for Climate Impact Research and has headed the International Institute for Applied Systems Analysis in Laxenburg near Vienna since 2023. To cool the Earth again after overshooting temperature targets, CO₂ will have to be removed from the atmosphere. Besides technical methods with underground disposal, he names what he calls the forest-construction pump: fast-growing trees and grasses such as bamboo, which grows 40 metres in six years, take up CO₂ that then remains locked away in construction timber and furniture for the long term. Almost 40 percent of global emissions today come from the building sector.

That is how I want to turn the biggest climate offender, the building sector, into the biggest climate hero.

Actively transforming forests

Schellnhuber considers it wrong to assume that forests can only survive climate change if they are left completely alone. Many of today's human-shaped forests will not survive the overshoot phase. That is why active intervention is needed: planting tree species that can cope with the future climate and reforesting, including degraded areas of the Amazon. This approach currently gives him the greatest hope of limiting the overshoot phase.

How Timber Carbon sees it

The forest-construction pump describes the principle on which carbon removals in timber construction are based. Timber Carbon, launched in 2026 as a spin-off of Timber Finance, quantifies, certifies and monetises the carbon removed in mass timber buildings as carbon removal credits on the voluntary carbon market. The article Forests in transition shows how the idea was already framed as a “second forest” in 2023, and our Technology page explains the current standard.