Current scenarios used by the IPCC do not differentiate between natural forest regrowth, reforestation with plantations, and afforestation of land not previously tree-covered, which makes assessment of biodiversity impacts difficult and is a knowledge gap that needs to be addressed.

Gaps remain, however, in moving beyond theoretical concerns to the design of practical frameworks but are essential to address fragmented legal and governance regimes across multiple governance scales.

Many of the ecological SDG goals have lack a focus on ecosystem functions or integrity, as well as insufficient attention to feedbacks (Reyers & Selig, 2020).

Offsets in particular raise complicated governance questions for both biodiversity and climate, and the effectiveness of regulations of these sectors is unclear.

The body of evidence regarding the ability of the adoption of agroecological principles to achieve multiple benefits within agricultural landscapes (including improved conservation) is growing – although research gaps remain (see, for example, Wanger et al. (2020), and their discussion of a research agenda for agroecology). )

Estimates of non-monetary and indirect benefits of REDD+ are lacking due to a lack of expertise and inadequate information about environmental and biodiversity benefits (Rakatama et al., 2017).

The vast majority of these models do not, however, account for important mechanisms of adaptation (Razgour et al., 2019; Settele et al., 2014).

The capacities and limits to adaptation for the vast majority of species are not well known due to lack of sufficient data (Urban et al., 2016; IPBES, 2019; Razgour et al., 2019)

Marine ice loss in the Arctic has many consequences in addition to these. The net outcome of changes in primary production in open Arctic waters, loss of benthic production from under-ice algae, loss of pagophilic (ice-dependent) species and lower albedo is as yet unclear so we cannot yet reach any clear conclusions on Arctic mitigation potential (Rogers et al., 2020).

The fate of the extra captured carbon is unknown, including potentially harmful disruption in the marine food web (Hoegh-Guldberg et al., 2019.