00:00This is probably how you imagine a green city.
00:04Tower blocks surrounded by plants, rooftop gardens, tree-lined streets.
00:10But for most Europeans, that's not a reality.
00:14As climate extremes become more frequent and severe,
00:18European cities are under pressure to adapt.
00:22The European Union has set a clear target.
00:25No city should lose green space or tree cover by 2030.
00:29And from 2031 onwards, urban green space should be expanded
00:34until it meets satisfactory levels.
00:37However, greening a city is not just about planting more trees.
00:42Because, if done wrong, it can lead to new problems.
00:46So, how do you green a city the right way?
00:50The World Health Organization recommends that everyone should live within 300 metres of a park or green area.
01:03In Europe, just fewer than half of city residents do.
01:07In fact, the only capital cities with more than 15% of their land occupied with green space are Stockholm, Athens and Dublin.
01:17In Ljubljana, that's just 1%.
01:20But the map changes if you look only at trees.
01:24Ljubljana leads Europe in tree canopy coverage, followed by Vilnius and Zagreb.
01:30This means millions of Europeans are missing out on the benefits that green spaces offer.
01:36Parks, gardens and trees are not only aesthetically pleasing,
01:41they can also lower temperatures, improve air quality and absorb excess rainfall.
01:47Research shows that our mental wellbeing is closely linked to how well we handle heat stress.
01:53However, if not well planned, in certain situations, vegetation can have the opposite effect.
02:01In some cases, in function of the geometry of the streets and how the city is planned,
02:08some streets can increase the level of air pollution.
02:12Because trees and their dense canopies, they can trap air pollution,
02:17especially if it's a street where a lot of motorized transport is passing by.
02:23Because it traps the atmospheric layer, it reduces the wind speed.
02:28So very locally, you can have increased levels of air pollution.
02:32And there's something similar happening with heat stress.
02:36That's why, for the Swedish researcher Jenny Linden,
02:40urban planners need to look beyond parks and trees.
02:44If you only look for trees, you're very limited in what you can put in the city outside of parks.
02:50Then it's just a few places where there's actually room for trees.
02:55But green walls, they provide cooling for the building,
03:01reduces the energy need for cooling inside the building.
03:06Same for green roofs.
03:07And although they don't have the same benefits as trees,
03:11they do increase the total leaf area.
03:14So they increase how much pollutants are removed from the air
03:19as they get stuck on the leaves instead of exposed to us.
03:24But choosing the right type of greenery is part of the challenge.
03:29When it comes to tree planting, researchers say it shouldn't be about how many trees are planted,
03:35but which ones and where exactly.
03:39Without proper guidance, we could be planting the wrong species in the wrong places.
03:45Cities that planted just one species learn this the hard way.
03:50The main focus should be site specific tree selection.
03:54Like they need to tolerate the site today and tomorrow.
03:57But we have a big issue in Europe that we have a very limited diversity of trees.
04:03And Amsterdam and Malmö have an experience when you lose a lot of trees.
04:10They did it because they have planted a lot of elms.
04:13And then the Dutch M disease came and there are areas in Amsterdam and Malmö that lost all the trees.
04:20They have to start all over again.
04:22This is very fragile because if these overused species get hit by a disease or a pest,
04:28and you lose a large amount of trees, you also lose all these benefits and ecosystem services.
04:35Most researchers agree. If Europe does not get urban greening rights, many cities could become unlivable.
04:46The challenge is making sure the vegetation we plant today will still be healthy decades from now.
04:53So, which is why you are now?
04:54Let's look at our website now.
04:55Let's see here now.
Comments