International Conference

“Photosynthesis Research for Sustainability”

More than 3 billion years ago biology developed the capacity to efficiently capture solar energy and use it to power the synthesis of organic molecules. This photosynthetic process set into motion an unprecedented explosion in biological activity allowing life to prosper and diversify on an enormous scale as witnessed by the fossil records and by the extent and diversity of living organisms on our planet today. Indeed, it was the process of photosynthesis over eons of time which has provided us with the oil, gas and coal  needed to power our technologies, heat our homes and produce the wide range of chemicals and materials that support everyday life.

Today, it is estimated that photosynthesis produces more than 100 billion tons of dry biomass annually, which would be equivalent to a hundred times the weight of the total human population on our planet at the present time and equal to about 100 TW of stored energy. The success of this energy generating and storage system stems from the fact that the raw materials and energy needed to drive the synthesis of biomass are available in almost unlimited amounts; sunlight, water and carbon dioxide. At the heart of the reaction is the splitting of water by sunlight into oxygen and hydrogen. The oxygen is released into the atmosphere where it is available for us to breathe and to use for burning our fuels. The ‘hydrogen’ is not normally released into the atmosphere but instead is combined with carbon dioxide to make organic molecules of various types.  When we burn fuels we combine the ‘stored hydrogen’ of these organic molecules with oxygen. Similarly energy is also released from organic molecules when they are metabolised within our bodies by the process of respiration. Thus in the biological world photosynthesis brings about the splitting of water into oxygen and ‘hydrogen’, respiration being the reverse, combining oxygen and hydrogen in a carefully controlled and highly efficient way so as to create metabolic energy. It is important to appreciate that all energy derived from the products of photosynthesis (food, biomass, fossil fuels) originates from  the energy falling on our planet in the form of sunlight.

Against this background it is anticipated that the global demand for energy will more than double by the mid-century and perhaps more than triple by the end of the century. Satisfying this demand will be necessary in order to achieve vibrant technological progress, economic growth and most importantly, political stability over the coming decades. Already we are faced with the prospect of catastrophic climate change due to the release of carbon dioxide into the atmosphere brought about by the burning of fossil fuels. For these reasons it is vital that we encourage a new generation of scientists to exploit and extend our present day knowledge of the photosynthetic processes.

There are two avenues that must be explored with vigour: To continue to improve our knowledge of the molecular processes which underlie photosynthesis and plant metabolism to engineer plants to have high solar energy conversion efficiencies.  To establish as a matter of urgency a multidisciplinary effort to construct robust artificial systems able to efficiently used solar energy to split water and have the capacity to either release the hydrogen or use it to reduce carbon dioxide to fuels like methane and methanol. Our improved understanding the molecular processes of photosynthetic energy conversion can be combined with developments in photovoltaics and nanotechnology to develop new technologies for solar energy capture and conversion. Unlike a biological leaf this artificial equivalent could, for example, be placed in arid deserts areas of our planet. Because of this the ‘artificial leaf’ will not compete for cultivatable land in the way that massive biomass production will.