More than half of common plants and one third of animals could see a dramatic decline this century due to climate change, a pioneering research project has discovered.

An international team of researchers based in the UK and Australia looked at 50,000 globally widespread and relatively common plant and animal species with a view to finding out how climate change projections could affect their range and populations. Their findings were extremely worrying; if nothing is done to reduce global warming and slow down the rate of climate change, one half of the plants and one third of the animals studied will shrink globally and biodiversity will decline almost everywhere.

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The risk to plants, reptiles and particularly amphibians is expected to be most severe. Sub-Saharan Africa, Central America, Amazonia and Australia would lose the most species of plants and animals, and a major loss of plant species is projected for North Africa, Central Asia and South-eastern Europe.

However, although the study's predictions are grim, the authors estimate that swift action to mitigate climate change could reduce the forecast losses by 60 per cent and buy an additional 40 years for species to adapt. This is because this mitigation would slow and then stop global temperatures from rising by more than two degrees Celsius relative to pre-industrial times (1765). Without this mitigation, global temperatures could rise by 4 degrees Celsius by 2100.

Lead author Dr Rachel Warren, of the University of East Anglia and Tyndall Centre for Climate Change Research explained the study's importance; "While there has been much research on the effect of climate change on rare and endangered species, little has been known about how an increase in global temperature will affect more common species. This broader issue of potential range loss in widespread species is a serious concern as even small declines in these species can significantly disrupt ecosystems."

Speaking to Farming Online on Friday (10th May), Dr Warren warned that the predicted species loss would have devastating knock-on effects for humans, through affecting vital ecosystem functions on which we rely, including water and air purification, flood mitigation, pollination, pest control and nutrient cycling amongst others. She said "predicted declines are likely to impact on food production, [although] we are not yet in a position to quantify the potential impact; we have also analysed impacts on wild crop types."

Dr Warren continued "We examined the effect of rising global temperatures, but other symptoms of climate change such as extreme weather events, pests, and diseases mean that our estimates are probably conservative. Animals in particular may decline more as our predictions will be compounded by a loss of food from plants."

Call for immediate action to avert disaster

Warren and her associates called for "swift action to reduce CO2 and other greenhouse gases," which their modelling suggests would avert the worst predicted scenarios. Dr Warren said, "Prompt and stringent action to reduce greenhouse gas emissions globally would reduce these biodiversity losses by 60 per cent if global emissions peak in 2016, or by 40 per cent if emissions peak in 2030, showing that early action is very beneficial. This will both reduce the amount of climate change and also slow climate change down, making it easier for species and humans to adapt."

However, somewhat depressingly, she stated that appropriate action to avert the species collapses and declines predicted in her research can only be taken on a policy level, by national and international governments and organisations with the power to shift the current paradigm to achieve reductions in emissions, adding that action on the ground by individuals or small groups will be mostly ineffective.

She did suggest, "Actions that can be done on the ground will still be needed to help biodiversity adapt to the 2^oC rise that will still happen, for example developing protected area networks and landscape scale conservation efforts that take account for a 2^oC rise."

The effects on some species can be seen in the Wallace Initiative database, which graphically displays potential impacts on a large number of the plants and animals studied. Dr Warren said, "Some [species] of note include pineapple, cotton, coffee, tea, chocolate (at least in terms of effects on their ranges)."

Although the investigation revealed clear potential for species declines to drastically affect human health and wellbeing, Dr Warren said the impacts of loss or reduction of individual species have not yet been fully studied. She reiterated that the study focused on plants and animals that are currently common and that, as such, their contributions to ecosystem health are often taken for granted, and revealed that the next stage of the team's research will attempt to quantify the potential effects on ecosystem functions.

She said, that while this means there are not currently any illustrative examples to demonstrate the gravity of the situation, "the importance of the research lies in the average impacts upon the set of 50,000 species that we studied."

"To look at a particular species would require particular study of that species and its ecology," Warren added. "Work we plan to do on pollinators will probably fill this gap; we will look globally at pollinators of agricultural crops and their projected losses."