Over the past 100 years, the global average temperature has increased by approximately 0.6 degrees C and is projected to continue to rise at a rapid rate. Although species have responded to climatic changes throughout their evolutionary history, a primary concern for wild species and their ecosystems is this rapid rate of change. We gathered information on species and global warming from 143 studies for our meta-analyses. These analyses reveal a consistent temperature-related shift, or 'fingerprint', in species ranging from molluscs to mammals and from grasses to trees. Indeed, more than 80% of the species that show changes are shifting in the direction expected on the basis of known physiological constraints of species. Consequently, the balance of evidence from these studies strongly suggests that a significant impact of global warming is already discernible in animal and plant populations. The synergism of rapid temperature rise and other stresses, in particular habitat destruction, could easily disrupt the connectedness among species and lead to a reformulation of species communities, reflecting differential changes in species, and to numerous extirpations and possibly extinctions.

Extreme heat stress during the crop reproductive period can be critical for crop productivity. Projected changes in the frequency and severity of extreme climatic events are expected to negatively impact crop yields and global food production. This study applies the global crop model PEGASUS to quantify, for the first time at the global scale, impacts of extreme heat stress on maize, spring wheat and soybean yields resulting from 72 climate change scenarios for the 21st century. Our results project maize to face progressively worse impacts under a range of RCPs but spring wheat and soybean to improve globally through to the 2080s due to CO 2 fertilization effects, even though parts of the tropic and sub-tropic regions could face substantial yield declines. We find extreme heat stress at anthesis (HSA) by the 2080s (relative to the 1980s) under RCP 8.5, taking into account CO 2 fertilization effects, could double global losses of maize yield ( Y = −12.8 ± 6.7% versus −7.0 ± 5.3% without HSA), reduce projected gains in spring wheat yield by half ( Y = 34.3 ± 13.5% versus 72.0 ± 10.9% without HSA) and in soybean yield by a quarter ( Y = 15.3 ± 26.5% versus 20.4 ± 22.1% without HSA). The range reflects uncertainty due to differences between climate model scenarios; soybean exhibits both positive and negative impacts, maize is generally negative and spring wheat generally positive. Furthermore, when assuming CO 2 fertilization effects to be negligible, we observe drastic climate mitigation policy as in RCP 2.6 could avoid more than 80% of the global average yield losses otherwise expected by the 2080s under RCP 8.5. We show large disparities in climate impacts across regions and find extreme heat stress adversely affects major producing regions and lower income countries.

Climate change is expected to have significant influences on terrestrial biodiversity at 21all system levels, including species-level reductions in range size and abundance, 22 especially amongst endemic species 1-6 . However, little is known about how mitigation of 23 greenhouse gas emissions could reduce biodiversity impacts, particularly amongst 24 common and widespread species. Our global analysis of future climatic range change of 25 common and widespread species shows that without mitigation, 57±6% of plants and 26 adaptation. 34The IPCC 3 estimates that 20-30% of species would be at increasingly high risk of 35 extinction if global temperature rise exceeds 2-3°C above pre-industrial levels. However, 36 since quantitative assessments of the benefits of mitigation in avoiding biodiversity loss are 37 lacking, we know little about how much of the impacts can be offset by reductions in 38 greenhouse gas emissions. Furthermore, despite the large number of studies addressing 39 extinction risks in particular species groups, we know little about the broader issue of 40 potential range loss in common and widespread species, which is of serious concern as even 41 small declines in such species can significantly disrupt ecosystem structure, function and 42 services 7 . 43Here we quantify the benefits of mitigation in terms of reduced climatic range losses 44 in common and widespread species, and determine the time early mitigation action can "buy" 45 3 for adaptation. In particular, we provide (i) a comprehensive analysis of potential climatic 46 range changes for 48,786 animal and plant species across the globe, using the same set of 47 global climate change scenarios for all species; and (ii) a direct comparison of projected 48 levels of potential climate change impacts on the climatic ranges of species in six 21 st century 49 mitigation scenarios, including a 'no policy' baseline scenario in which emissions continue to 50 rise unabated (Fig. 1, Table 1). To calculate the climatic range changes, we employed 51MaxEnt, one of the most robust bioclimatic modelling approaches for cases where only 52 presence data (as opposed to presence-absence) are available 8 . MaxEnt models the 53 probability of a species' presence, conditioned on environment 8 so that in this paper 'climatic 54 range change' specifically refers to the change in the modelled probability of a species' 55 occurrence, conditioned on climatic variables. Eighty percent of the species studied have 56 climatic ranges in excess of 30,000 km 2 , which is the range size used by Bird Life 57International to delineate 'restricted range species', whilst less than 7% have ranges 58 occupying less than 20,000 km 2 ( Supplementary Fig. S1). Our study therefore focuses on 59 quantifying the effects on widespread species, which are in general more common and less 60 likely to become extinct than restricted range species 9 , in contrast to previous studies that 61 have only speculated that there may be effects such species [1][2][3][4][5][6] . In projecting future...

In the Paris Agreement on Climate Change, the United Nations is pursuing efforts to limit global warming to 1.5°C, whereas earlier aspirations focused on a 2°C limit. With current pledges, corresponding to ~3.2°C warming, climatically determined geographic range losses of >50% are projected in ~49% of insects, 44% of plants, and 26% of vertebrates. At 2°C, this falls to 18% of insects, 16% of plants, and 8% of vertebrates and at 1.5°C, to 6% of insects, 8% of plants, and 4% of vertebrates. When warming is limited to 1.5°C as compared with 2°C, numbers of species projected to lose >50% of their range are reduced by ~66% in insects and by ~50% in plants and vertebrates.