Human intervention in forested ecosystems is hoped to perform a fundamental shift within the next decade by reverting current forest loss—a major source of CO2 emissions—to net forest gain taking up carbon and thus aiding climate change mitigation. The demanded extensive establishment of forests will change the local surface energy fluxes, and with it the local climate, in addition to competing with food and fibre production for land and water.
Scenario building models encompass this competition for resources but have turned a blind eye to the biogeophysical (BGP) local surface energy flux disturbance so far. We combine the benefit of CO2 sequestration of afforestation/reforestation (A/R) with the additional incentive or penalty of local BGP induced cooling or warming by translating the local BGP induced temperature change to a CO2 equivalent.
We then include this new aspect in the land-use model Model for Agricultural Production and their Impact on the Environment (MAgPIE) via modifying the application of the price on greenhouse gases (GHGs). This enables us to use MAgPIE to produce A/R scenarios that are optimised for both their potential CO2 sequestration and the CO2 equivalent local BGP effect, as well as the socio-economic trade-offs of A/R.
Here we show that optimal A/R patterns are substantially altered by taking the local BGP effects into account. Considering local cooling benefits of establishing forests triples (+203.4%) the viable global A/R area in 2100 from 116 to 351 Mha under the conditions of the shared socioeconomic pathway 2 (SSP2) scenario driven by the same GHG price. Three quarters (76.0%, +179 Mha) of the additionally forested area is established in tropical climates alone.
Therefore, a further neglect of BGP effects in scenario building models undervalues the benefit of tropical forests while simultaneously running the risk of proposing counterproductive measures at high latitudes. However, the induced focus on tropical forestation intensifies the competition with food production where forests contribute most to mitigation. A/R related trade-offs need to be considered alongside their climate benefit to inhibit unintentional harm of mitigation efforts.
Coastal loss and damage for small islands
This commentary on a paper in Nature Sustainability reviews how the study quantifies the impacts of sea-level rise on small island states and estimates the impacts in terms of cost, land loss and population exposure across all small islands worldwide.
Adjusting 1.5°C climate change mitigation pathways in light of adverse new information
This study uses an integrated assessment model to explore how 1.5°C pathways could adjust in light of new adverse information, such as a reduced 1.5°C carbon budget, or slower-than-expected low-carbon technology deployment.
2030 targets aligned to 1.5°C: evidence from the latest global pathways
Our new method applies sustainability limits and minimises the need for carbon dioxide removal to set key 2030 global targets for renewables, fossil fuels and emissions.
The deployment length of solar radiation modification: an interplay of mitigation, net-negative emissions and climate uncertainty
Here, we investigate the deployment timescales of solar radiation modification and how they are affected by different levels of mitigation, net-negative emissions and climate uncertainty.
Emissions as usual: implications for the Safeguard Mechanism of LNG and coal mine projects
This report examines the implications of committed and proposed developments in the LNG and coal mining sectors for reform of Australia's Safeguard Mechanism.
Uncompensated claims to fair emission space risk putting Paris Agreement goals out of reach
Only halving emissions by 2030 can minimise risks of crossing cryosphere thresholds
1.5°C is still in reach to reduce the worst climate risks – but only with immediate mitigation action and shifting finance
How can the EU transform its economy to meet the 1.5°C goal?
What does the 1.5°C goal require from EU climate policy? This 4i-TRACTION policy brief analyses the latest 1.5°C-aligned scenarios and spells out what they imply for EU climate policy.
Institutional decarbonisation scenarios evaluated against the Paris Agreement 1.5°C goal
This study analyses six institutional decarbonisation scenarios published between 2020 and mid 2021 (including four from the oil majors and two from the International Energy Agency. It finds that most of the scenarios would be classified as inconsistent with the Paris Agreement as they fail to limit warming to ‘well below 2 ̊C, let alone 1.5 ̊C, and would exceed the 1.5 ̊C warming limit by a significant margin.