Climate change impact on animals

According to a recent study, the effects of climate change on animals would have cascading effects on nutrition, environment, behaviour, physical health, and mental health, among other five categories of welfare.

The study was published in CABI Reviews.

The study emphasises the need for researchers to carefully consider which areas are of immediate and long-term importance in order to protect the welfare and longevity of animals used for food production, as domestic pets, and for conservation in zoos and nature reserves.

Bats, zebrafish, stony creek frogs, koalas, African elephants, chickens, and dairy cows are among the animals at risk from the effects of climate change that are mentioned in the review.

Although there are variations in how different animals react biologically to stress, it is argued in the review that the five domains model offers a reliable tool for research use and to assess the immediate effects of climatic variability on animals. The study provides a broad overview of the impacts of climate change on animal welfare, drawing on examples from various animal groups across terrestrial and aquatic habitats, encompassing both wildlife and domesticated species.

Dr Edward Narayan, lead author and Senior Lecturer of Animal Science in the School of Agriculture and Food Science at The University of Queensland, Australia, said, “While researchers have extensively examined the effects of climate change on animals, the direct correlation between climate change and animal welfare, particularly in the context of wild animals, remains relatively scarce in existing studies."

“In this review, our research group – The Stress Lab – presents a series of wildlife and domesticated animals examples from various countries, across both aquatic and terrestrial systems and provides an overview of the impacts of climate change on each of the five domains of animal welfare."

“We hope that future researchers will apply the animal welfare domains to evaluate how climate change impacts on animals, and further research will pave the way to protecting animals from the catastrophic impacts of climate change.”

The review highlights research that shows how heat stress, for example, in dairy cows has resulted in a 35 per cent reduction in milk production. Heat stress significantly impacts lactation performance, immune function, and calf health.

However, monitoring cows' activity and rumination time helps detect heat stress, and appropriate heat dissipation strategies such as sunshades and sprinklers can mitigate its effects, the researchers suggest.

It also argues that broiler chickens kept under hot conditions for four days showed higher cases of necrosis – reducing the quality of their life and meat. The welfare of birds, especially mature broilers, under warmer conditions, is of great concern.

Birds have a limited capacity for heat regulation as they lack sweat glands, and regulate temperature by panting, limiting their activity and drinking more. Accordingly, air conditioning units may be required to maintain an optimal production temperature.

Drought and scarcity of resources are also key contributors to the death of elephants, the scientists highlight. They argue that as the largest extant terrestrial mammal, the African elephant has significant daily food and water needs.

But as droughts become more frequent and predictable, water and vegetation cover availability declines, increasing elephant heat and nutrition stress, contributing to the elevated elephant mortality currently being witnessed.

The study also stresses that climate change has been recognised as a major factor in driving population declines across many species of marsupial, including the koala.

Increasing mean temperatures mean species such as the koala will be required to expend more energy to maintain body temperature, using a food source that is reduced in quality due to current climate change projections.

And even the domestic cat and dog is affected by climate change, according to scientists. They say, for instance, that certain breeds of dogs are susceptible to heat stroke while heat-related diseases are a leading cause of death in military working dogs.

Around half of all dogs in the UK are overweight with insufficient exercise being a factor and weather conditions can be a potential hindrance to dog walking. The review highlights that 87% of owners report that they exercise their dogs less during hot weather. The gradual increase in global temperature has the potential to decline the level of welfare for dogs which, the scientists say, may also lead to changes in the role of dogs in human society.

Dr Narayan added, “As climate change drives more wild populations to ecological limitations, there will be potential welfare consequences and considerations to explore; for example, when vulnerable species would need to be transferred to new environment" (e.g., captive breeding), should food and habitat become limiting resources.

“Likewise, production animals and other domesticated species will be impacted by the extreme environment">environmental changes with consequences on each of the dimensions within the five domains of animal welfare.”