MARK TWAIN ONCE said “everybody talks about the weather, but nobody does anything about it”.

The weather certainly does grab the headlines. Especially when a catastrophic event like Hurricane Isaac ploughs into the southern US states causing, it is estimated, nearly $2.5 billion worth of economic loss.

Isaac was only a category one storm, but its toll on the US Gulf Coast exceeded what one might expect from a “low-end” tropical storm. So as soon as the rain stopped, and the floods began to subside, people started to talk about Isaac and climate change.

Weather and climate

At this point it’s important that we stop and understand that there is a clear difference between every day weather events like Hurricane Isaac and our planet’s climate system.

To understand this distinction we need to think of weather as the day-to-day chaotic fluctuation of our planet’s atmosphere. Is it hot, is it cold, is it wet is it dry? This is weather. Climate on the other hand makes up the trends and patterns in weather over relatively long periods of time. We need to think of climate as summer, autumn, winter or spring. The kind of weather we are likely to experience over a certain time period.

Weather tells us what clothes we should wear. Climate tells us what clothes we should buy.

The scientific evidence supporting climate change is now overwhelming. In fact I would suggest that anyone who says that our planet is not warming simply doesn’t understand the science or holds an ideological position that can’t process the science. There is no more doubt that our planet is warming and this is a result of human activity.

Evidence

We know empirically that our planet is absorbing more energy than it is emitting and this is directly linked to the increase of greenhouse gases in our atmosphere because of burning fossil fuels.

A recent study by NASA scientists at the Goddard Institute for Space Studies used global recorded temperature data, rather than prediction models to show that climate change is responsible for recent extreme weather events. The author of the study, Dr James Hansen explained the recent increase in extreme weather events by saying that the chances of these events happening naturally – without climate change – is negligible.

If Mark Twain was around today he’d probably say “everybody talks about climate change, but nobody does anything about it!” The evidence of global warming is all around us.

Prior to Hurricane Isaac, June 2012 marked the warmest 12 month period in the US since record-keeping began in 1895. Globally, June 2012 has seen the all-time warmest average land surface temperature since record-keeping began in 1880.

Carbon Emissions

Humans are now emitting around 30,000,000,000 tonnes of CO2 into the atmosphere every year. When scientists measure the type of carbon accumulating in the atmosphere, they observe more of the type of carbon that comes from burning fossil fuels. Oxygen levels in the atmosphere are falling in line with the amount of carbon dioxide rising. Basic combustion chemistry.

Satellites are measuring less heat escaping out into space at the particular wavelengths that CO2 absorbs it. The green house effect. As greenhouse gases stop this heat from reaching the upper atmosphere, a distinct greenhouse signature is a warming the lower atmosphere and cooling the upper atmosphere.

Our planet is also warming faster at night than it is during the day. Another scientific phenomenon in line with increasing greenhouse gas concentrations in the atmosphere.

I could go on and I’m sure some climate change deniers will respond to this article with their usual half truths, myths, distortions and cherry picking of “scientific fact”. ButI will preempt them now. They are wrong, they are in denial.

Elizabeth Kubler Ross, a Swiss American psychiatrist, defined five stages that people go through when they receive catastrophic news. The five stages are denial, anger, bargaining, depression and finally acceptance.

Maybe the reason we are all talking about climate change but doing nothing about it is that we don’t yet accept the clear evidence of science. Unfortunately that’s not very smart – because time is running out!

Gavin Harte has been a spokesperson on environmental and sustainability issues in Ireland for many years. He has worked as the national director of An Taisce and was the founder and developer of Ireland’s first eco-village in Cloughjordan Co Tipperary and now runs ESD Training, his consultancy for Education on Sustainable Development.