New research published in Science today shows that climate-change impacts have already impacted every aspect of life on Earth from genes to entire ecosystems, with increasingly worrying consequences for humans.
The article, "The broad footprint of climate change from genes to biomes to people", co-authored by Dr Wendy Foden from Stellenbosch University, has been published in Science today (11 November 2016). Dr Foden is also chair of the International Union for the Conservation of Nature's (IUCN) Species Survival Commission and Climate Change Specialist Group (CCSG) where the study originated.
In the study, researchers identified a set of core ecological processes that underpin the functioning of healthy ecosystems. Of the 94 processes considered and published in peer-reviewed literature, 82% showed robust evidence of impacts from climate change. These impacts include changes to genetic diversity or seasonal migration, all which influence the functioning of healthy marine, freshwater and terrestrial ecosystems.
"These climate change impacts are deeply concerning, and are more extensive than we expected. It is clear that climate change is a major concern, not for the future, but now," Dr Foden says.
Dr Brett Sheffers, lead author of the article from the University of Florida and also a member of the IUCN SSC CCSG group, says they now have evidence that, with only a ~1oC of warming globally, major impacts are already being felt. These range from individual genes changing, significant shifts in species' physiology and physical features such as body size, to species moving to entirely new areas.
The researchers warn that the many observed impacts of climate change at different levels of biological organisation points to an increasingly unpredictable future for humans in terms of food security and human health. Healthy ecosystems contribute to climate mitigation and adaption by sequestering substantial amounts of carbon, regulating local climate and reducing risks from climate-related hazards such as floods, sea-level rise and cyclones, the report states.
"This study has strong implications for the world leaders gathering for climate negotiations in Marrakesh." says Dr Foden. "Countries are currently committing to reduce global temperature rise to around 3oC. But we are showing that there are already serious impacts right across biological systems at an increase of only 1oC. If we are going to keep natural systems delivering the services we rely so heavily on, it is imperative that we step up our efforts."
She says many of these impacts have already been observed in Africa. A 2007 study found that Southern Africa's Quiver Trees (Aloe dichotoma) have been suffering from high mortality and poor reproduction in their hot, arid northern distribution range in Namibia due to increased drought stress. However, at their southern range edge in South Africa, where conditions were previously at the limit of their tolerance for cool, wet conditions, populations have been rapidly expanding.
A 2016 study attributes declining fishing yields from Africa's Lake Tanganyika to changes in lake circulation due to warming of surface waters. Other studies have documented the impact of climate change on food security, such as the decline of maize yields in Africa. The outbreak of diseases such as Babesia and canine distemper virus (CDV) in 1994 and 2001 that killed over one-third of the Serengeti lion population was also the result of a cycle of processes, initiated by climate change. Researchers attributed the disease-outbreak to a combination of viral infections, blood parasites and extreme weather events.
Prof Guy Midgley, head of the global change biology research group in SU's Department of Botany and Zoology, says the Science paper highlights what they have been seeing on the ground in South Africa: "Climate change impacts have now become wide-spread and are accumulating more quickly than we expected. It is essential that we act decisively and quickly to reduce our greenhouse gas emissions worldwide."
The full study can be accessed here.
Media interviews
Dr Wendy Foden
E: fodenw@gmail.com
Tel: +44 793 280 4214
Skype: wendyfoden;
Prof. Guy Midgley
E: gfmidgley@sun.ac.za
Tel: +27_21 808 3223
