Williams JW, Jackson ST, Kutzbach JE. Projected distributions of novel and disappearing climates by 2100AD. Proc Natl Acad Sci USA 104: 5738-5742

Department of Geography, 550 North Park Street, University of Wisconsin, Madison, WI 53706, USA.
Proceedings of the National Academy of Sciences (Impact Factor: 9.67). 05/2007; 104(14):5738-42. DOI: 10.1073/pnas.0606292104
Source: PubMed


Key risks associated with projected climate trends for the 21st century include the prospects of future climate states with no current analog and the disappearance of some extant climates. Because climate is a primary control on species distributions and ecosystem processes, novel 21st-century climates may promote formation of novel species associations and other ecological surprises, whereas the disappearance of some extant climates increases risk of extinction for species with narrow geographic or climatic distributions and disruption of existing communities. Here we analyze multimodel ensembles for the A2 and B1 emission scenarios produced for the fourth assessment report of the Intergovernmental Panel on Climate Change, with the goal of identifying regions projected to experience (i) high magnitudes of local climate change, (ii) development of novel 21st-century climates, and/or (iii) the disappearance of extant climates. Novel climates are projected to develop primarily in the tropics and subtropics, whereas disappearing climates are concentrated in tropical montane regions and the poleward portions of continents. Under the high-end A2 scenario, 12-39% and 10-48% of the Earth's terrestrial surface may respectively experience novel and disappearing climates by 2100 AD. Corresponding projections for the low-end B1 scenario are 4-20% and 4-20%. Dispersal limitations increase the risk that species will experience the loss of extant climates or the occurrence of novel climates. There is a close correspondence between regions with globally disappearing climates and previously identified biodiversity hotspots; for these regions, standard conservation solutions (e.g., assisted migration and networked reserves) may be insufficient to preserve biodiversity.

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Available from: John W Williams, Oct 20, 2015
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    • "By 2080 no suitable habitat is predicted within the Wet Tropics bioregion for 84% of species, under all emission scenarios. Although further work is required to link climate tolerances to the distribution of these species, these results are consistent with projections that have been previously conducted for other mountaintops worldwide (Williams et al., 2007) and Australia-wide (Williams et al., 2012). Current levels of climate change are considered unprecedented for observed events over the last 2000 years. "
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    ABSTRACT: Species inhabiting tropical mountaintops may be most at risk from the detrimental effects of climate change. Yet few regional assessments have critically assessed the degree of threat to species in these habitats. Here we model under three climate scenarios the current and future suitable climate niche of 19 plant species endemic to tropical mountaintops in northeast Queensland, Australia. The suitable climate niche for each of the 19 species is predicted to decline by a minimum of 17% and maximum of 100% by 2040 (mean for all species of 81%) and minimum of 46% (mean for all species of 95%) by 2080. Seven species are predicted to have some suitable climate niche space reductions (ranging from 1 to 54% of their current suitable area) by 2080 under all three climate scenarios. Three additional species are projected to retain between 0.1 and 9% of their current distribution under one or two of the climate scenarios. In addition to these declines, which are predicted to occur over the next 30 years in northeast Queensland, we discuss and outline pressing research priorities that may be relevant for the conservation of biodiversity on tropical mountaintop environments across the globe. Specifically, further research is needed on thermal tolerances, acclimation potentials, and physiological constraints of tropical mountaintop taxa as current species distributions are primarily determined by climatic factors.
    Full-text · Article · Nov 2015 · Biological Conservation
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    • "More importantly, detailed monitoring allows a rapid response in case of early warnings of maladaptation at the early stages of population establishment (Benito-Garzó n et al., 2013; IUCN, 2013). In fact, we should always expect some level of maladaptation in AM because latitudinal and altitudinal changes cannot compensate exactly for climate change and also because expected climates cannot be compared with either 20th century conditions (Williams et al., 2007) or other climates in the recent geological past (Benito-Garzó n et al., 2014). The question remains open of what level of maladaptation would be acceptable for the translocation to be considered acceptable. "
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    ABSTRACT: Assisted migration (AM) is increasingly proposed to limit the impacts of climate change on vulnerable plant and animal populations. However, interpretations of AM as a purely precautionary action along with multiple definitions have hampered the development of precise policy frameworks. Here, our main objective is to identify what type of policy tools are needed for implementing AM programs as part of broader environmental policies. First, we argue that policy frameworks for translocations of endangered species that are subject to climatic stress are fundamentally different from translocations to reinforce climatically exposed ecosystems because the former are risky and stranded in strict regulations while the latter are open to merges with general landscape management. AM implementation can be based on a series of phases where policies should provide appropriate grounds closely related to extant environmental principles. During a “Triggering phase”, AM is clearly a prevention approach as considered by the Rio Declaration, if unambiguously based on evidence that population decline is mainly caused by climate change. During an “Operational phase”, we suggest that policies should enforce experimentation and be explicit on transparent coordination approaches for collating all available knowledge and ensure multi-actor participation prior to any large scale AM program. In addition, precautionary approaches are needed to minimize risks of translocation failures (maladaptation) that can be reduced through redundancy of multiple target sites. Lastly, monitoring and learning policies during an “Adaptive phase” would promote using flexible management rules to react and adjust to any early alerts, positive or negative, as hybridization with local individuals may represent an evolutionary chance. Our analysis of study cases indicates that except for two programs of productive forests in Canada, current AM programs are predominantly small-scale, experimental and applied to endangered species isolated from general environmental management. As the effects of climate change accumulate, policies could include AM as part of larger environmental programs like habitat restoration with common species seeking to provide stable ecosystems in the future.
    Full-text · Article · Aug 2015 · Environmental Science & Policy
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    • "We defined summer as June to August and winter as December to February. We chose these variables because they constrain many plants and animals, are robust measures from climate models, and correlate well with other variables that act as constraints to plants and animals (Williams et al. 2007). We chose a high emissions scenario so that the vulnerability assessment would represent the worst case scenario from the options available in the climate model dataset . "
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    ABSTRACT: Determining where biodiversity is likely to be most vulnerable to climate change and methods to reduce that vulnerability are necessary first steps to incorporate climate change into biodiversity management plans. Here, we use a spatial climate change vulnerability assessment to (1) map the potential vulnerability of terrestrial biodiversity to climate change in the northeastern United States and (2) provide guidance on how and where management actions for biodiversity could provide long-term benefits under climate change (i.e., climate-smart management considerations). Our model suggests that biodiversity will be most vulnerable in Delaware, Maryland, and the District of Columbia due to the combination of high climate change velocity, high landscape resistance, and high topoclimate homogeneity. Biodiversity is predicted to be least vulnerable in Vermont, Maine, and New Hampshire because large portions of these states have low landscape resistance, low climate change velocity, and low topoclimate homogeneity. Our spatial climate-smart management considerations suggest that: (1) high topoclimate diversity could moderate the effects of climate change across 50% of the region; (2) decreasing local landscape resistance in conjunction with other management actions could increase the benefit of those actions across 17% of the region; and (3) management actions across 24% of the region could provide long-term benefits by promoting short-term population persistence that provides a source population capable of moving in the future. The guidance and framework we provide here should allow conservation organizations to incorporate our climate-smart management considerations into management plans without drastically changing their approach to biodiversity conservation.
    Full-text · Article · Jun 2015 · Ecosphere
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