Arguments
Can animals and plants adapt to global warming?
What the science says...
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Global warming will cause mass extinctions of species that cannot adapt on short time scales. |
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Climate Myth...
Animals and plants can adapt
[C]orals, trees, birds, mammals, and butterflies are adapting well to the routine reality of changing climate." (source: Hudson Institute)
At a glance
Just like “the climate has changed before”, this is another vague and unsubstantiated talking point. It is essentially meaningless because again it omits details – and details matter. Yes, some plants and animals can adapt – think of invasive plants like Japanese knotweed or annoying pests like rats. They seem to get on just fine under a wide range of conditions.
Other species, however, have evolved to fit into much narrower ecological zones. Think of Alpine plants: in a warming climate they may be able to extend their natural range uphill as the permanent snow-line retreats, but where can they go once they've reached the mountain-top?
On average, species that can migrate are moving some six kilometres polewards a decade, but such movements are not necessarily successful. For example, a butterfly may attempt to extend its range polewards, but if its food-plants do not grow in the territory it migrates to, then its caterpillars will have nothing to eat. Is that a recipe for success? Finally, whilst some species are capable of quickly migrating to places with more favourable physical conditions, others are not. A coral reef cannot simply pack up and move, can it?
We can clearly see how we've also made things more difficult for many species to adapt. One only has to consider the combination of a warming climate, gradually shifting Earth's climatic belts toward the poles and the amount of alterations we've already made to the planet's surface. Species run short of options. They can either interact with us to a far greater extent or they dwindle away until they are gone.
There's a term that covers all of the above issues. Maladaptation. It means an inability to adapt to any change for a variety of reasons, but none of them to the advantage of the species in question. Any species put at disadvantage is going to struggle to survive long-term. It's a term that will inevitably become more familiar in a scenario involving ongoing, unmitigated climate change.
Another unwanted consequence of such changes is the emergence of zoonotic pathogens. These are things like viruses that have evolved to jump from other animal species to humans, bringing an increasing risk of pandemics. These are details that the person saying or writing, "animals and plants can adapt", is omitting from the conversation. Details always matter.
Please use this form to provide feedback about this new "At a glance" section. Read a more technical version below or dig deeper via the tabs above!
Further details
The natural world has already been under attack for centuries. Since the discovery of agriculture, humans have massively transformed the globe through the expansion of civilization, to the detriment of Earth’s biodiversity. Great swathes of temperate forest in Europe, Asia and North America have been cleared for agriculture, timber, and urban development. Tropical forests in South America and Africa are now on the front line. Human-assisted invasions of pests, competitors, and predators are rising exponentially and overexploitation of fisheries and forest animals for meat have already driven many species to the point of collapse.
The ways plants and animals adapt to changes in their environment often involve migrating to areas with relatively favourable conditions (Bartley et al. 2019). But now, in order for many species to migrate large distances they would have to cross large areas of human influence. Mass migration in areas of large human population – entwined with crisscrossing, high-speed highways and polluted, dammed-up rivers – is self-evidently a challenging task.
Along with that, it has been shown that climate change has already had an impact on the environmental cues that animals use to determine the timing and navigation of their migratory patterns (Seebacher & Post 2015). Subsequently, these changes in animal migratory behaviour have also been shown to have a detrimental effect on the animal’s average lifespan and overall health.
There is much evidence that we are already on the brink of a mass extinction event. Because of human activity, the number of species on the planet is already decreasing. According to the Millennium Ecosystem Assessment (an international environmental report with the goal of assessing the impact of ecosystem change on human well-being), 60% of the world’s ecosystems are now degraded. The global rate of extinction is already at 100 to 1000 times that of the “normal” background rate on geological timescales. Mass-extinction events, marked in the fossil record, have typically taken place over a long time period compared to human history. But we can say one thing with certainty: rapid, anthropogenic climate change and environmental degradation is only making things worse for Earth’s biodiversity.
If we fail to prevent catastrophic climate change, there will be many regions of the world (some of which are highly populated) which will become uninhabitable to even us humans. This is based on human physiology and future temperature and humidity predictions under climate change. When temperature and humidity levels are too high – indicated by something scientists call a high “wet bulb temperature” – the human body is not able to cool itself by sweating. Extended periods of these high wet bulb temperatures, increasing the rate of heat stroke and death in humans are expected by later this century under medium to high emission scenarios (Newth & Gunasekera 2018), especially in tropical regions (fig. 1).
Fig. 1: Projected ten-year maximum monthly mean Wet-Bulb Globe Temperature by 2091-2100 under different Representative Concentration Pathway (RCP) scenarios. WBGT is derived from the Wet Bulb Temperature and near-surface air temperature as a proxy for globe temperature. Adapted from Newth & Gunasekera (2018).
Right now, only 1% of the Earth’s land is considered a “barely livable” hot zone, mainly within the Sahara and other desert regions. If emissions continue unregulated and climate change continues unmitigated, this fraction could increase to 19% by 2070. Billions of people live in these potential, future hot zones. Due to the current state of the global economy, many disadvantaged people residing in these potentially deadly places may not be able to move away or adapt.
In summary, the current outlook on Earth’s biodiversity is gloomy. We know that most mass extinctions in the fossil record have been triggered by the rapid onset of global warming due to an increase in carbon dioxide emissions to the atmosphere. In the past, these emissions were usually due to large, volcanic episodes which occurred over tens to hundreds of thousands of years. On a geological timescale, these changes occurred in the blink of an eye, and this is why they were so costly. The human-caused climate change that is occurring today is similar; since 1850, we have increased atmospheric CO2 levels to the highest they have been in the last 3 to 5 million years.
Even though all of this may be depressing, there is still hope. There is still time to reverse the worst effects of man-made climate change, and to do so we must reduce consumption, support conservation efforts and transition to renewable energy. For all of human history we have depended on Earth’s biodiversity, and it now depends on us to save it.
Last updated on 8 August 2024 by John Mason. View Archives
Re: Anthony's post about Candian geese, @50: Here in Colorado we refer to them as 'illegal residents.' They are also here now, year-round, and I clearly remember this not being the case 30+ years ago. No wonder: We feem them so well with our over-irrigated Kentucky blus grass lawns, and excessive non-native trees, coupled with the fact of shorter, warmer winters, they made the Adam Smith rational choice, and stayed over.
Responding to tkman0 question asked here
It's helpful if you provide sources to where you got your understanding to better understand the question. However, if you read the article above it should help. Ease of adaption depends on the rate of change. It takes time for suitable soils to develop for instance and the change is not merely about temperature but also changes in precepitation etc. Climate change does not affect hours of sunlight either.
tkman0 asks elswhere:
Well, this page asserts it, but does not explain it. Discussion is at least on topic here. So:
Tree ranges do in fact migrate with temperatures. This has been well established from evidence of response to the warming at the end of the last glacial using data from pollen and other plant remains:
It is also evident in Europe, where there are a large number of species confined to one or a few mountains, the result of gradual migration up the mountain slope as the Earth warmed with the consequent genetic isolation allowing the evolution of new species.
Migration in response to AGW faces three major limitations.
First, migration may simply be not physically possible. The alpine species mentioned above, for example, have an obvious limit to their migration with increasing warming such that any whose lower altitude range is within 600 meters of the summit will go extinct with a regional temperature rise of 4 C. Indeed, they may go extinct with a smaller temperature rise in that as the population approaches the summit, a smaller and smaller population can be supported leaving them vulnerable to extinction by chance fluctuations on population due to disease, predation or unusual weather. Similar issues face species near northern coastlines (in the NH). A regional rise in temperature of 4 C will do for (at least locally) most species whose southern limit is within 600 km of a northern coastline:
In addition to these obvious bariers, east-west mountain ranges, or even large scale changes in underlying soil type can present natural bariers to migration, and hence potential exinction threats.
More importantly in the modern world is that human activity has created a very large number of additional bariers to migration (the second limitation). Put simply, seeds from trees that land in cornfields do not grow to maturity. Nor, come to that, do they typically grow to maturity in pasturage. The vast farmlands developed by humans across the NH represent a major barier to the migration of the range of trees.
Finally, and most importantly, the third barrier is the simple pace of temperature change. We are currently facing an increase of temperature of about 3 C over the coming century. That equates to a distance of about 450 km of change in latitudinal range to preserve current species health. Trees that propogate by dropping seeds can change there range at a few hundred meters per generation at most. (They can do so much faster if the seeds are dispersed by birds, and to a lesser extent winds.) Given the pace at which climate is changing, they well simply be left behind.
The effect will be complicated. Intuitively that means their northern range will not expand as rapidly as their southern range retreats - but that is not necessarilly true. For trees, like most life forms, the greatest competition comes from other species rather than from the environment itself. This is shown by the shere range of environments in which trees protected from competition by being in gardens can grow. It follows that the southern range will only retreat rapidly if some competitor species can advance quickly. So the actual likely result (IMO) is that long lived, slow growing species will be displaced by short lived quick growing species across the range.
Thanks for the replies everyone, also just wanted to point out that some of the links on here dont link to articles, but insteasd link simply to a general climate change page at the univeristy of texas.
tkman0
The latest IPCC report has this graph about species movement rates vs warming rates
There was an interesting find I saw published in the journal of Nature Communications published September 2014:Central Europe Tree Growth
That's interesting, a 75% increase in growth rate in beech trees in parts of Europe.
My personal inclination is simply to work to manage forests responsibly.
Protagorias,
I saw an interesting find where it described that 25% of the trees in Texas over 4" diameter at breast height were killed by the drought they have had. In California the current drought is the worst in the past 1200 or more years. Fires alone have killed millions of trees. Do you think the increase in trees in Central Europe is more or less than the decrease in trees in the American West? What should we do to manage the forests more responsibly in the face of historic droughts?
Looking deeper I found this reference which is more reliable and suggests only about 5% of Texas trees were killed by the 2011 drought. I stand by my point that managing forrests will produce little return in the face of historic drought.
michael sweet,
Climate change is undoubtedly happening at a very rapid and uncomfortable pace. And droughts are obviously a big concern.
Perhaps what can produce a lot of return in the long run, be economocially sound jobs, as well as potentially help in managing forests and mitigating drought, is to gain the technology to unlock some of the water locked up the ringwoodite inside our planet. I think there's something like two or three times the volume of the world's oceans locked up in ringwoodite, but it's around 500 miles down.
Once desertification takes hold it is an irreversible process. That is not to say the rain won't fall elsewhere yet where and in what proportion?
The concept of non-linearity means there are no promises!
Who can tell me if the economic rise of China has yet been reflected in the Keeling curve, for instance?
To Anthony @50: Don't know much about birds but mentioning "migration" reminded me of a doco I saw the other night(about "song-birds" I think!?!) that said birds in the Northern hemisphere and the Southern hemisphere act differently. I think there may be a climatic reason to it but I can't remember what it was!
This is appeal to nature fallacy. Just because some species exist, doesnt mean it's necessarily good that they continue to exist. Also, "animals/plants can adapt" doesnt necessarily mean every specie will adapt. it means life in general will adapt and create new forms of animals who, guess what, can now survive in the new climate. Throughout history catastrophic events changed entire climate of the planet in a day. and yet life survived, and flourished. So this entire appeal to nature fallacy is wholly uninteresting to me.
guad,
You are factually incorrect. An appeal to nature is an argument or rhetorical tactic in which it is proposed that "a thing is good because it is 'natural', or bad because it is 'unnatural'".
Whereas this article focuses on actual things that are bad...because they would be bad whether natural or not. Ecosystems have functions. We call this ecosystem services. You might want to read up on it, since it is what keeps you alive. Ecosystem services
"ost extinctions have been linked to immense volcanic events, called Large Igneous Province (LIP) eruptions. These events spew billions of metric tonnes of carbon dioxide (CO2) and sulfur dioxide (SO2) into the atmosphere, in many cases triggering marine anoxia (oxygen loss) and ocean acidification due to rapid greenhouse warming. Of the Big Five mass extinctions, the one exception is the end-Cretaceous event. The current scientific consensus is that the end-Cretaceous mass extinction (that wiped out the dinosaurs 66 million years ago) was primarily caused by a large meteor strike (and a resulting, jarring change in climate). In Figure 1, the past three events (end-Permian, end-Triassic, and end-Cretaceous) are positioned at their respective, estimated short-term CO2 spike levels. These CO2 spikes which triggered their respective mass extinctions are not captured in the grey CO2 concentration curve due to its coarser temporal resolution."
I read where the Tubo volcano about 2MYA resulted in a long cooling period caused by the sun's rays reflecting off the ash in the air. I would think that would decrease atmospheric greenhouse gasses. Mass extinctions resulted including nearly all our homonid ancestors, with survivors limited to small populations in Africa.
https://www.npr.org/sections/krulwich/2012/10/22/163397584/how-human-beings-almost-vanished-from-earth-in-70-000-b-c
@Hal Kantrud
Your NPR link is about the postulated Toba bottleneck some 70,000 years ago (not 2 million). There's a lot of problems with that postulate (the most obvious of which is that the "Hobbits" on Flores just 2,767.5 km or 1,719.6 miles away survived that "bottleneck" by many thousands of years). A volcanic eruption, while it might provide some short-term climate impacts (a few years to a few decades), has no mechanism by which it can drive atmospheric CO2 levels down over any meaningful period. Temperatures, CO2 and sea levels had been declining before Toba and continued apace afterwards. The global impacts of Toba on human evolution are considered to be minimal (more similar discussions).
Please note: the basic version of this rebuttal was added on May 29 and includes an "at a glance“ section at the top. To learn more about these updates and how you can help with evaluating their effectiveness, please check out the accompanying blog post @ https://sks.to/at-a-glance
We also moved the existing intermediate version to a new advanced version and then updated the intermediate version, so that now all three rebuttal versions exist for this myth.
Thanks - the Skeptical Science Team.