What are the risks of climate change? How will sea levels rise and how will that affect us? How can science and technology make a real difference? How can we make clean energy and a clean environment a low cost option? Few people know more about this topic than Steven Chu, Nobel laureate in Physics and former US Secretary of Energy.

In Denmark, they have very concrete plans for how their entire society should switch to renewable energy sources. How does that work? Professor Katherine Richardson is a member of the Danish Commission on Climate Change and knows all about it.

If we are all going to drive electrical cars in the future, battery technology must improve. New discoveries in materials science is the key to success. One of the leading experts in the field is Jean-Marie Tarascon from France.

Being both a member of the Parliament in the United Kingdom, and a scientist – Dame Julia King has a large influence on her country’s energy policy. What does the UK need to do in order to meet the climate goals – at least an 80% reduction in CO2 emissions by 2050?

Pi-conjugated organic molecules and polymers are being increasingly used in various applications such as light-emitting diodes (LEDs) in smart-phone displays, and photovoltaic diodes. Sir Richard Friend from Cambridge explains the physics of these organic semiconductors that enable us to produce cheap and flexible materials that can even be processed by direct printing.

Nanoscience has given us new possibilities to design materials that absorb and emit light and transport charges efficiently. Paul Alivisatos, a pioneer in the field, has developed small pieces of semiconductors, “quantum dots”, used in a new generation of extremely energy efficient displays that provide exceptional color purity. Could quantum dots enable entirely new energy conversion systems and spectacular devices in the future?

Singlet fission is a photophysical process which could make solar cells much more efficient. Unfortunately, it proceeds efficiently in only very few known materials, and none of these are very practical. Josef Michl is engaged in a search for and testing of simple structural guidelines for the design of new materials that perform singlet fission efficiently.

Thin film solar cells are considered the next generation of photovoltaic technology because of their lower use of materials and energy, compared to conventional solar cells. Additionally, they can be made flexible and light weight, which opens a range of new applications. Susanne Siebentritt summarizes the state of this technology and the latest developments in the research laboratories.

Daniel G. Nocera from Harvard shows that using only sunlight, air and water, a distributed system may be established for the production of fuel and food. Such science will be particularly useful to the poor of the world, where large infrastructures for fuel and food production are not tenable. Hear the story of the artificial leaf!

To replace fossil fuels with renewably generated fuels from sunlight is a grand challenge for humanity. Harry Atwater from Caltech talks about how far we have reached in creating artificial solar fuel generators for hydrogen generation, and how we may accomplish efficient CO2 reduction.