The warm days of summer, when we have them, are filled with the sounds of bees humming away in flowering bushes and the sweet smell of meadow grass. Frost on an autumnal morning abruptly halts the growth of plants and sends the remaining insects into sheltered nooks and crannies.
The seasonal ebb and flow of nature is intimately linked to weather on a day to day basis and climate over longer time periods. People born and bred in the tropics are shocked when they see an alien landscape of dead looking winter deciduous trees in a seasonal climate like ours. It is a reminder of how strongly climate shapes our view of what is natural and normal.
Changes in climate will change the rhythms of nature. Biodiversity, the variety of different life forms in nature, will be altered. Some Irish species will do well in the warmer summers we are having and the reduction in frost days over winter will lead to longer growing seasons for species which can take advantage of these higher temperatures.
Other species will respond poorly to longer and more intense summer droughts and waterlogging in winter. There will be a reshuffling of the biodiversity deck, with a loss of some cards and a gain of others.
This great reshuffling of biodiversity will lead to changes in how ecosystem services, like water filtration and carbon capture, function in Irish landscapes. Ecosystems, the collection of species in an area that interact with the physical environment, may collapse or change substantially.
If common species in woodlands, bogs, oceans and grasslands are affected by climate change we could see major disruptions in the supply of critical ecosystem services that underpin our agricultural, forestry, angling, marine and tourism industries. For some ecosystems, change may be gradual and buffered by the long life span of some plants, animals and fungi. For other ecosystems, changes will be abrupt and intense.
Pressures
The capacity of ecosystems to resist and recover from climate change will depend on how many other pressures are affecting them. Biodiversity is already declining due to the destruction of habitats through land use change, pollution, invasive species and overharvesting, even before the effects of our current climate change trajectory are felt strongly.
These pressures strongly limit how ecosystems can respond to climate change. A bog which is already pushed to its biological limits through overharvesting, overgrazing and which is overrun with invasive Gunnera plants will be less able to respond to intense winter rain coupled with moisture sucking summer droughts.
Climate change is one of several direct threats to biodiversity. There are other ties that bind climate and biodiversity together. Nature provides solutions to move us away from the existential crisis of business-as-usual climate scenarios. Plants along river banks and in salt marshes can protect us from erosion and flooding.
Green roofs and walls provide our urban spaces with clean air, insulation, flood protection and resources for pollinators. Plants in forests, bogs, permanent grasslands and oceans pull carbon from the atmosphere and sequester or store it in their bodies as wood, as soil carbon and in seabed sediments.
To get the these benefits, we need to protect what we have by reducing pressures on biodiversity and to restore ecosystems where they have been removed or damaged. There are win-win opportunities for both climate and biodiversity.
There are also win-lose scenarios where actions to mitigate climate change can lead to loss of biodiversity. This would have the effect of prioritising the ecosystem service of carbon storage and sequestration above the integral values of biodiversity and the many other services it provides.
The biodiversity of the planet provides us with a deck of options for supporting our survival and wellbeing. Some cards are more useful for one ecosystem service game than another. We are playing many games simultaneously and in any one of those games the rules could change suddenly.
Maintaining biodiversity is like maximising the number of different cards in your hand so you can respond to rule changes quickly and effectively. In a rapidly changing system we should not be gambling with biodiversity by betting it all on yesterday’s game.
Yvonne Buckley is an ecologist and professor of zoology at Trinity College Dublin