Global transport accounts for almost one quarter of energy-related carbon dioxide emissions, and the proportion is rising.

When Justin Bieber made his way to Stockholm in September 2016, city officials hardly expected the tween heartthrob to pave the way for sustainable urban policy .

Livestock produces a lot of waste. One solution is to turn such agricultural waste into biogas to generate energy .  It requires using so-called anaerobic digestion, which consists in breaking down biodegradable material in the absence of oxygen.