Milan in Italy is often plagued by muggy, almost tropical weather. However, an ambitious plan to plant three million new trees by 2030 could offer relief from the stifling weather. As well as helping to lower temperatures, the trees will play a major role in mitigating pollution and combating global warming.

Officials estimate that boosting the number of trees by 30% in the broader metropolitan area will absorb an additional five million tons of carbon dioxide each year (four-fifths of the total produced by Milan), plus reduce harmful PM10 small particulates by 3,000 tons over a decade. They also predict the new trees will reduce city temperatures by a significant 2C.

Renowned architect Stefano Boeri said the current green canopy of the Lombard region’s capital accounts for only 7% of the urban area – well below other European cities, like Frankfurt at 21.5% or Amsterdam at nearly 21%.

The plan is to increase this green canopy to between 17% and 20% by 2030 and, ultimately, lower

temperatures in a city where the evening mercury can be 6C (10.8F) higher than in the surrounding area.

According to city statistics, Milan endures around 35 tropical nights a year. Because of its location close to the Alps, there is very little wind to clear pollutants that become blocked in by temperature inversions, where a layer of cool air is covered by a layer of warmer air.

Plus, as Damiano Di Simine, the scientific coordinator in Lombardy for the environmental group Legambiente, describes, this also contributes to urban heating.

“It means the discomfort from thermic inversions is terrible, because the climate is very stationary. Planting trees will help this”, Mr Di Simine said.

Some ad-hoc projects have already contributed to environmental improvements, such as Mr Boeri’s Vertical Forest residential towers, completed in 2014. However, if Milan’s plan is any indication, the Vertical Forest is just the beginning.