Building a ‘green’ economy – with a special focus on energy – is seen as a key strategy to reduce greenhouse gas emissions and prevent dangerous climate change. For countries without vast fossil-fuel reserves, it is also a way to gain energy independence and security.

Yet it is also becoming clear that resource constraints could hinder this endeavour. Low-carbon technologies such as photovoltaics, wind turbines, and electric and hybrid cars, for example, use metals that are mined only in a handful of countries, which can limit their availability. Biofuels development, meanwhile, has raised concerns that fuel crops will displace food crops – or displace forests and vitally important ecosystems. In addition, these crops compete for what are often limited water resources.

As low-carbon power production increases, it too often competes for water supplies that, in many regions, are already being tapped at unsustainable levels. With population growth, rapid urbanization, and the projected impacts of climate change, there is concern about the viability of not just hydropower, but also solar thermal, geothermal and other renewable technologies that require water for cooling.

If low-carbon energy is to be produced on a large scale – a must in order to keep global temperature increases under 2°C – it is crucial to recognize these real resource constraints and respond appropriately. The reports recommend strategies for both the public and private sectors.