 |
| Wildflowers proliferating in overgrown roadsides during the coronavirus pandemic are providing habitat for pollinators. (Shutterstock) |
Authors
|
Wildlife sightings are increasing, air quality is improving and carbon emissions are dropping. While these glimmers of positivity cannot come close to eclipsing the tragic human cost of the coronavirus, many are now asking what the pandemic will mean for wildlife around the globe.
Global carbon dioxide emissions for 2020 are expected to fall by up to eight per cent due to shutdowns, although the resumption of global activity could increase emissions and offset some of these gains. While this is a significant reduction in our expected emissions, it’s far from enough to turn the tide on climate change’s impacts on biodiversity.
Climate change can’t be stopped by COVID-19. This past April and May were both tied for the warmest on record, and if this trend continues then June will be the 426th month in a row where global average temperatures are above the 20th-century average. This serves as a strong reminder that even if we stop all carbon emissions today, we will still be fighting to reduce emissions and sequester carbon for a long time. The stakes are dangerously high.
Lessons from the bees
We’ve known for a while that bumblebees and many other species have been declining over recent decades. Finding the driver of these declines is especially important for a group of pollinators that performs irreplaceable ecosystem and agriculture services.
Recently, we showed that there is strong evidence that climate change has played a role in the declines of bumblebees across North America and Europe. In this new work, we found a mechanism that links climate change to these pollinator declines: climate chaos.
 |
| Bombus ternarius, the tricoloured bumblebee, seen on Manitoulin Island, Ont. (Peter Soroye) |
As Hamlet noted, “ay, there’s the rub.”
Wildlife can tolerate some degree of warming, either by finding ways to move away from risky weather or evolutionary adaptation. But it’s much more difficult for species to tolerate increasingly chaotic extremes in weather such as prolonged drought and heat waves, or tropical storms.
100 years of bumblebee data
For bumblebee species, we could predict local extinction and colonization of new areas by estimating whether recent climate change had subjected species to temperatures beyond any they are known to have tolerated in the past.
Through a series of tests with a dataset including over 100 years of bumblebee observations, we found that species have disappeared in places where temperature spiked above what they could tolerate. Species across North America and Europe are consistently being pushed to the edges of these limits during the year, much more often than they ever were for most of the 20th century. Increasing intensity of land use — including increased pesticide use — also harms bees, but these effects are distinct from the dangerous signal of climate chaos.
Average annual temperatures (map) and monthly extremes (shown in the right-hand inset with year in red compared to a baseline period in grey) have been increasing across North America and Europe from 1975-2015, resulting in declines for the bumblebees (estimated average annual decline for a species shown in left-hand inset)
While our recent study focused on bees, increasing extremes from climate change should, in principle, affect other species in the same way. If this is the case, then the increasing temperature or precipitation extremes above (or below) the limits of what species can tolerate could rapidly and abruptly begin reshaping ecosystems around the globe by as early as 2030.
Necessary responses
Although we’ll feel the effect of climate change for decades, it’s necessary to address its causes now while we still have reasonable prospects of mitigating its worst impacts. Strategies like maintaining sheltered micro-habitats to provide shade or cover, and keeping a diversity of habitats in a landscape can help reduce exposure of species to extreme weather.
Perhaps, humanity’s lighter touch during the pandemic of 2020 will mean more species can traverse landscapes or make it through another hot year in landscapes that are a little less disturbed. For instance, the profusion of wildflowers in unmaintained roadside verges could create a large amount of nesting and foraging habitat for pollinators if left for the whole year.
The growing number of gardens that are appearing as people spend more time at home could provide a similar benefit. As with reductions in emissions, continuing these practices long after lockdowns end will be the deciding factor in whether they make a difference for pollinators and other wildlife.
In some places, species and ecosystems are bouncing back, although this is not true everywhere: as economies suffer, poachers are killing protected wildlife.
The glimmers of hope will never make the incalculable human toll of a global pandemic worthwhile, nor its economic costs. Yet, hope remains a vital tool to motivate action to address climate change.
Climate change isn’t locked down and it isn’t practising social distancing. It is accelerating the erosion of the planet’s life support systems and the decline of species that humanity would be hard pressed to do without. Concerted global action can make dangerous situations better, whether it’s a pandemic or the climate crisis.
Links
- IEA: Coronavirus impact on CO2 emissions six times larger than 2008 financial crisis
- COVID-19 lockdowns significantly impacting global air quality
- Daily global CO2 emissions ‘cut to 2006 levels’ during height of coronavirus crisis
- Carbon Emissions Are Decreasing During the Pandemic but Could Bounce Back Fast
- Coronavirus closures could lead to a radical revolution in conservation
- May 2020 tied for hottest on record for the globe
- Global warming pushes April temperatures into record territory, as 2020 heads for disquieting milestone
- The world’s biodiversity is declining at an alarming rate
- Microhabitats reduce animal's exposure to climate extremes
- Growing your own food during the coronavirus pandemic? Plan for pests!
