How can we make our cities more livable without spending a lot of money ?
More than 80% of the European population is expected to live in urban areas by 2030 (Fig.UNECE). At the same time, recurrent heat waves make the life of the population in large towns always more difficult. They particularly affect the huge urban areas resulting in temperatures as much as 12°C higher than in less -developed surrounding areas.Yet, and worldwide an annual estimated investment of close to $100 million, which is very reasonable, in tree planting initiatives could provide as many as 68 million people with significant reductions in fine particular matter levels and also a reduction of 1°C in air temperature (Fig.P.Mittermaier - Nature Conservancy). Fortunately, it seems that leadership at the highest level is beginning to realize the consequences of rapid urbanization for the world : "We live in century of unprecedented urban growth.For the first time in history, cities are home to more than half of the humanity.By 2050, two out of every three people on earth will live in urban areas (S.G.UN Gutteres 8 May 17).Cities are confronted with major challenges such as air pollution, noise nuisance and globally with sustainable use of natural resources.Against this background, it is not surprising that urban dwellers are suffering increasingly from diseases linked to this poor environment.We stress only one figure in the latest report of the World Health Organization (WHO): every year, ambient (outdoor) air pollution causes nearly 500,000 premature deaths in European countries.In such an hostile environment more green spaces in urban areas are essential for improving the quality of life for all citizens especially when 92% (Fig.WHO) of the world's population is already exposed to dangerous air pollution.Accordingly, let us simply begin by planting more trees!