We need to find a better way of communicating more clearly what we do know, eg warming is very likely man made, and what we are less sure of eg. precise numerical warming or rainfall changes in particular regions. Even this first statement has its problems. What does very likely mean? Greater than 90% chance. Well what does that mean?
We need to be able to relate our science to everyday life and the decisions that people are making. If we do this then it is possible to convey complex messages. For example the problems of sea level rise for a low lying island may first be manifested as contamination of ground water. This is simple to a scientist and easy to understand when explained but conveys that the impacts of climate change may be complex.
The difference between weather and climate, and natural and man-made change is a constant source of confusion that is exploited by those who would like to spread confusion about climate change. It is very tempting to jump to conclusions that climate change is speeding up or slowing down because of short term changes such as the slowing of global temperature rise in the last 10 years or the speed up of Arctic ice loss in 2007. We should all remember the headlines about a slowing of the thermohaline circulation a few years ago - which it is now apparent was temporary.
Very often we are working through journalists as intermediaries. We would like to think that they can help us to communicate the science in an accessible way. Often they do this very well if we give them the right help - we need to make sure we give clear concise messages. However, their real job is to sell their newspaper, radio station etc. This means that they may pick the quote that gives the best headline one week and criticise you for giving it to them (or more likely their rival newspaper) the next week.