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Viable nature-based climate solutions (NbCS) are needed to achieve climate goals expressed in international agreements like the Paris Accord. Many NbCS pathways have strong scientific foundations and can deliver meaningful climate benefits but effective mitigation is undermined by pathways with less scientific certainty. Here we couple an extensive literature review with an expert elicitation on 43 pathways and find that at present the most used pathways, such as tropical forest conservation, have a solid scientific basis for mitigation. However, the experts suggested that some pathways, many with carbon credit eligibility and market activity, remain uncertain in terms of their climate mitigation efficacy. Sources of uncertainty include incomplete GHG measurement and accounting. We recommend focusing on resolving those uncertainties before broadly scaling implementation of those pathways in quantitative emission or sequestration mitigation plans. If appropriate, those pathways should be supported for their cobenefits, such as biodiversity and food security.

mRNA turnover is an important regulatory component of gene expression and is significantly influenced by ribonucleoprotein (RNP) complexes which form on the mRNA. Studies of human alpha-globin mRNA stability have identified a specific RNP complex (alpha-complex) which forms on the 3' untranslated region (3'UTR) of the mRNA and appears to regulate the erythrocyte-specific accumulation of alpha-globin mRNA. One of the protein activities in this multiprotein complex is a poly(C)-binding activity which consists of two proteins, alphaCP1 and alphaCP2. Neither of these proteins, individually or as a pair, can bind the alpha-globin 3'UTR unless they are complexed with the remaining non-poly(C) binding proteins of the alpha-complex. With the yeast two-hybrid screen, a second alpha-complex protein was identified. This protein is a member of the previously identified A+U-rich (ARE) binding/degradation factor (AUF1) family of proteins, which are also known as the heterogeneous nuclear RNP (hnRNP) D proteins. We refer to these proteins as AUF1/hnRNP-D. Thus, a protein implicated in ARE-mediated mRNA decay is also an integral component of the mRNA stabilizing alpha-complex. The interaction of AUF1/hnRNP-D is more efficient with alphaCP1 relative to alphaCP2 both in vitro and in vivo, suggesting that the alpha-complex might be dynamic rather than a fixed complex. AUF1/hnRNP-D could, therefore, be a general mRNA turnover factor involved in both stabilization and decay of mRNA.