Editing IPCC:AR6/WGII/Chapter-2 (section)

=== 2.4.1 Overview ===

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Global meta-analyses of terrestrial systems in AR3 and AR4 concentrated on long time frames (&gt;20 years) and findings from relatively undisturbed areas, where confidence in attributing observed changes to climate change is ''high'' . Recent global and regional meta-analyses (AR5 and later) have been broader, including data from degraded and disturbed areas and studies with shorter time frames (Tables 2.2a,b).

By the time of AR5, &gt;4000 species with long-term observational data had been studied in the context of climate change ( [[#Parmesan--2006|Parmesan, 2006]] ; [[#Parmesan--2015|Parmesan and Hanley, 2015]] ). Since then, thousands of new studies and additional species have been added, leading to ''higher confidence'' in climate change attribution (Table 2.2) ( [[#Scheffers--2016|Scheffers et al., 2016]] ; [[#Wiens--2016|Wiens, 2016]] ; [[#Cohen--2018|Cohen et al., 2018]] ; [[#Feeley--2020|Feeley et al., 2020]] ). Freshwater habitats have been under-represented in prior reports, but new long-term datasets, coupled with laboratory and field experiments, are improving our understanding. This assessment stresses observations from lakes and streams. As numbers of studies increase and data is increasingly extracted from areas with high LULCC, attribution is more difficult as habitat loss and fragmentation are known major drivers of changes in terrestrial and freshwater species ( [[#Ramsar%20Convention%20on%20Wetlands--2018|Ramsar Convention on Wetlands, 2018]] ; [[#IPBES--2019|IPBES, 2019]] ; [[#Tickner--2020|Tickner et al., 2020]] ). Due to the overwhelming volume of literature, the assessments for chapter 2 concentrates on results from large continental or global-scale reviews and meta-analyses. Most of the assessment of studies conducted in individual countries can be found in Regional chapters, but this chapter does include studies across very large countries or political entities that occupy much of a continent (e.g., Canada, the USA, Australia or Europe), or studies that provide rare or uniquely-relevant information.

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