When extreme heat hits Ireland, we will thank the trees – The Irish Times

I’m lucky enough to have a patch of garden, and about five years ago I decided to transform a semi-shaded triangular patch of grass – about the size of three parking spaces – into a miniature forest. I crammed about 45 native trees together and, competing for sunlight, they grew well. Birds bounce from tree to tree, picking up moths and other insects along the way, and the soil is improved.

What surprises me is the microclimate in this room. When you stand in the middle of the place, the air feels cleaner, and on hot days there is a noticeably moist coolness. That makes sense, since trees are nature’s mist cooling systems; a network of tubes draws water from the roots in the ground up through the stems and leaves, where the water evaporates into the air, cooling the tree and its surroundings along the way.

But unlike man-made mist cooling systems, trees do this for free. A large oak tree can evaporate up to 400 gallons of water per day, and its wide canopy acts like an umbrella, reducing the amount of sunlight hitting the ground. A survey of 108 US cities found that the difference between the hottest and coolest neighborhoods was as much as 10 degrees Celsius, much of which was attributed to the spread of the trees.

We have to start thinking about how we can keep a cool head in the future. We’ve just come off the warmest May on record, which many of us probably barely noticed as it was influenced by higher nighttime temperatures. But we are quickly ratcheting up the tension, prompting UN Secretary General António Guterres to call for action. “Our planet is trying to tell us something. But it seems we are not listening,” he said last month. “Now is the time to mobilize, take action and deliver results.”

Last month, hundreds of the world’s leading climate scientists predicted a “semi-dystopian” future, driven by heat waves, floods and storms, with “major societal disruption” within the next five years, caused by an 80 percent probability that we will reach the 1.5 will exceed. degrees of warming during that period. We have failed to cut emissions fast enough to reach our 2030 target in Ireland, leaving our young people facing a difficult future.

So we need to consider worst-case scenarios and plan accordingly and as quickly as possible. The frequency of extreme heat and heat waves in Europe has increased since 2000. Two-thirds of people in Ireland live in urban areas in Dublin, where the population continues to grow, and exposure to heat hazards is expected to increase significantly in the coming decades. .

Urban areas have surfaces that absorb heat, such as concrete and asphalt, and not enough green spaces to cool things down. During hot summer days this can mean that rooms heat up like a frying pan. This ‘heat island’ effect in cities will increase as housing density and development expansion increase.

Some people are more sensitive to heat than others. Younger children, the elderly, outdoor workers, socio-economically disadvantaged people, pregnant women and the chronically ill are all disproportionately vulnerable to heat stress and mortality.

In April, Cork City Council approved a tree strategy that could see the city’s tree cover double to 30 percent in coming years. The planting of new trees will focus on neighborhoods with the lowest leaf cover, including areas ranked as deprived in Pobal’s Deprivation Index, such as Fairhill and Knocknaheeny. The aim is to plant trees together with the community and make the area greener.

Trees in urban areas offer more than just protection against a warming city. The evidence shows that living in a green environment is linked to a lower risk of diabetes, high blood pressure and heart attacks in adults. A 2015 study of urban centers in Canada found that having just a few more trees – about eleven or so – in an urban neighborhood reduced heart-related disease, comparable to increasing annual income by $20,000 (€13,500). More trees improve mood, reduce stress in pregnant women and make people feel more connected to each other.

None of this will be news to the people living on the Larchville/Lisduggan estates in the city of Waterford who have been regenerating their area with trees for years. A team of local volunteers have planted apple and plum trees, greened their urban spaces with flowers for butterflies and planted vegetables in raised beds. They have acted in favor of nature and left their community, classified as extremely disadvantaged, in a better state than before.

The Nature Restoration Act, which has the support of top executives from transnational companies such as Danone, Nestlé and Unilever, includes a plan to make our urban spaces greener. If it survives the European turn to the right in last week’s election and becomes law, it will mean that as our urban space grows to meet housing demand, our green space will not be lost, but will instead increase by 3 percent will increase. By 2050, we could have at least 10 percent tree cover in all our cities, towns and suburbs.

Trees are our cheapest and most effective bulwark against extreme heat. It is difficult to imagine a future when we suffer from severe heat waves in the summer. They are still rare here, but scientists are clear that this is changing. When the heat hits, we will be grateful to the trees and all they freely give us as we stand under their canopies and enjoy the cool shade.