Andreas Späth

Climate change guinea pigs

2016-01-18 11:23

Andreas Wilson-Späth

When it comes to national responses to the effects of climate change, many policy makers have shifted from focusing on mitigation to concentrating on adaptation – an acknowledgement of the fact that we have left things too late and will no longer be able to avoid the impacts regardless of what we do. In their minds the problem is now less about finding ways to fix things and more about how we can manage to live with the consequences.

Sadly, we’ve become the subjects of our own large-scale experiment – a macabre reality show of global survival. And, as in all good reality shows, there will be winners and losers, depending on our individual and communal capacity to deal with a warming planet. Actually, we’ll all be losers. Some will lose more than others.

But what about the plant and animal species we co-inhabit this place with? How will they cope with the changes we are causing? They’ve evolved to live in specific environmental circumstances which are going to be changing at an increasing pace. Some will be able to migrate to more suitable areas, but many won’t and they will have to face the outcomes head on. Evolution’s main driving mechanism of natural selection is, for the most part, too slow to keep everyone fit for survival in a rapidly changing world.

Luckily there is some good news, too. Ever resourceful, nature has tools that it can use to respond to some of the challenges climate change will throw at it, at least in the short term.

A great example of this, ironically, is the humble guinea pig. For a new study published in December, a group of scientists exposed a bunch of wild South American guinea pigs to artificially elevated temperatures for two months. In response, the animals underwent a series biochemical changes that turned at least ten genes in their DNA that are connected to the regulation of body temperature either on or off, making them more resilient to the heat.

This type of process is referred to as an epigenetic change in which a plant or animal’s observable traits are altered as a result of external factors without changing their hardwired genetic makeup. Whereas natural selection requires random changes to the DNA sequence itself, epigenetics merely involves genes being switched on or off in reaction to environmental effects. 

What’s more, epigenetic changes are heritable (i.e. passed on from parent to offspring). This offers a much faster way of adapting to climate variations than common garden variety evolution. As the authors of the paper note, “exposure to a temporally limited increased ambient temperature led to an ‘immediate’ and ‘heritable’ epigenetic response”. They add that “in the context of globally rising temperatures epigenetic mechanisms may become increasingly relevant for the survival of species”.

Their work represents the first time this sort of thing has been documented in wild mammals, but other experiments have shown it to be active in other species threatened by the changes wrought by global warming.

Heritable epigenetic effects resulting in a greater tolerance for rising temperatures have been shown to occur in populations of brine shrimps and Arabidopsis thaliana, a small Eurasian flowering plant.

Similarly, some species of coral are able to adapt to changes in marine conditions, especially ocean acidification (the increased acidity of seawater as a result of greater concentrations of CO2 absorbed from the atmosphere).

This type of research should not stop us from worrying about how plants and animals will cope with the rising temperatures we are exposing them to. It’s unknown which species have the ability of undergoing epigenetic adaptations and even for those that do, they don’t represent a long-term answer to the problem. Epigenetic changes may merely buy them some time, giving them a better chance to evolve more lasting solutions in the long run.

- Andreas is a freelance writer with a PhD in geochemistry. Follow him on Twitter: @Andreas_Spath

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