By Catherine Waite, University of Nottingham
Our society is inundated with information about climate change: it is in the news, infiltrating film and television, science, and policy. And yet misconceptions remain regarding the importance and prevalence of such change. Often, focus is placed entirely on the impacts to flagship species; the polar bear losing its icy home, for instance. Unfortunately, this example is just the tip of the iceberg. Climate change is affecting many more species than previously estimated and in myriad ways, including behavioural and physiological changes, as pointed out in a recent article in Geo: Geography and Environment (McCarthy et al., 2017).
A Redback Salamander (Plethodon cinereus)
Photo Credit: Brian Gratwick, Wikimedia Commons via CC BY 2.0
In this article, the authors investigated the effects of a warming climate on the body size of redback salamanders, finding that body size varies greatly depending on temperature. The salamanders were 2.3% larger in warmer areas versus cooler ones. Meanwhile a size increase of 1.8% was observed within areas that had experienced warming of 0.5-1.2oC between the periods 1950-1970 and 1980-2000. This is by no means the only species to have been affected by the changing climate. Both behavioural and physiological changes in other species have been noted: marmots now end their hibernation three weeks earlier compared to 40 years ago, martens in the Americas are getting bigger, and the skull shape of alpine chipmunks is altering due to climate pressure.
It is essential to recognise that such responses and adaptions do not mean that these species are successfully adapting to our warming world. Ecologists have noted that climate is changing too fast for species, as they cannot adapt fast enough to keep up with projected rates of future climate change (Jezkova and Wiens, 2016). So, even if the salamanders studied by McCarthy et al., (2017) seem to be adapting to, and tolerating, changes in temperature so far, they may not continue to do so in the future. The same can be said for other species; if they can’t adapt quickly enough, extinction may be the outcome, and we can forget the notion that this is purely a theoretical, future event. The first mammal global extinction due entirely to climate change has already been confirmed: the Bramble Cay molomys, an Australian rat-like rodent, went extinct due to rising sea levels inundating the coral island on which it lived.
Not many people have heard about the Bramble Cay molomys. They have heard about the polar bear or the Bengal tiger, though. These attention-grabbing species have been used as ‘flagships’ for conservation organisations, but are they any more important than their overlooked counterparts? Is it justifiable to focus on flagship species in an attempt to attract attention and money that can then be used to support conservation at larger scales? Or, is a disproportionate amount of conservation resources being spent on these flagship species? It’s a delicate issue, and one that few agree on. All we can do is remain aware that, even if the intent behind flagship species is to help raise attention and funds for wider conservation efforts, we can’t let them overshadow other, overlook, species that are also in trouble.
It has been suggested that “most species on Earth have been impacted by climate change in some way or another” (The Guardian, 2017). However, there has been enormous under-reporting of these impacts to date. The IUCN Red List only classes 7% of mammals and 4% of birds as threatened by climate change and severe weather. This is undoubtedly an underestimate, as many species wait decades for updates within the list and most of the Earth’s species have never been evaluated. Indeed, a study published in Science late last year found the current warming of just 1oC has already left marks on 77 of 94 different ecological processes, including species’ distributions and physical traits. This is supported by another study published in Nature Climate Change earlier this year, which found 47% of land mammals and 23% of birds have already suffered negative impacts from climate change. This huge difference in percentages from the IUCN Red List demonstrates how wrong we were about the numbers of species being affected by climate change. And the full extent is likely worse even than this. This research only considered two well-studied groups (mammals and birds) and the authors commented that we are likely to be significantly underestimating the extent of climate impacts on lesser studied groups even more. If we can be so wrong for our most studied groups, how much worse are our predictions likely to be for species we don’t know much about, like corals, bats, fungi and frogs?
Perhaps most disconcertingly, we have only experienced a relatively small amount of warming so far (~1oC), in relation to that predicted by the end of the century (4-5oC). When considering the changes that only 1oC of warming has wrought, it does not seem hyperbolic to say that the effects of further warming may be colossal. So what can we do? We need to change the way we think about and report climate change. It has been pointed out that many studies into climate change focus on forecasting, and tend to ignore the fact that our climate has already altered. When climate change is viewed only as a future threat, the impetus to do something today may be reduced. But climate change is happening now, and it is already having serious effects on many more species than we previously thought. Hopefully, with articles such as McCarthy et al.’s acknowledging alterations that have already taken place, we can begin to accept that changes are already affecting nearly all species on Earth; and that the time to act is now.
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McCarthy, T., Masson, P., Thieme, A., Leimgruber, P., and Gratwicke, B. (2017). The relationship between climate and adult body size in redback salamanders (Plethodon cinereus). Geo: Geography and Environment, 4:1.
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Leonelli, S.
