Elephants in the room? (Day 8)

It covers a sensitive and sometimes controversial issue - the growth of human population - but he also points out the power of individuals to make a difference.

Using Keith's words he says: "The elephant in the room with respect to climate change is the growth of the human population. I used to think that chemical engineers could do little until I read an article about a man in India who developed a simple machine for making sanitary towels."

It's a fascinating and inspiring story about engineering invention, passion, equality and also proves a counter-point to some of the negative media images of India seen in the news recently.

Again, using Keith's words, he says: "Research suggest that the human population will reach a maximum and that size of that maximum is very dependent on the education of women.

"The simple machine developed by the Indian gentleman [Arunachalam Muruganantham] enables women to earn enough to allow their daughters to go to school. So simple engineering solutions that allow the poor to earn more money (particularly women) will have a direct impact on the ultimate human population.

"This means that chemicals engineers can have a direct impact on the growth of the human population and that activities in this field may have more impact than all the other clever ways of reducing carbon dioxide in the atmosphere."

Some of Keith's comments are challenging and thought-provoking. Some people may not agree with all of them, but his message of empowerment and inequality - in all its forms - is yet another area where engineers and chemical engineers can make a difference.