I used to work as an engineering hydrologist, and an environmental manager. Multi-syllable words, but they meant I spent a lot of time collecting, analysing and using climate data, mostly rainfall and streamflow. And so I also did some reading on the then fledgling science of climate change.
I am also a christian, so I believe God wants us to care for his world, the people, yes, but also the animals and the earth itself.
So here’s a report on the state of the climate in the only world we have.
Six things everyone should know about climate
It’s all connected
Our climate is affected by many things – the sun, daily and annual temperature variation, the composition of gases and particles in the atmosphere, the rotation of the earth, the pattern of winds, the amount of water “locked up” in Arctic and Antarctic ice, and so on. What happens in one place can affect what happens far away.
Climate is very variable
Earth experiences large scale but slow changes – ice ages and more temperate eras. Climate (rainfall, temperature, etc) also varies from year to year, from day to day and from place to place. This variation can be large, and so we can get (especially in Australia) severe droughts and destructive floods, sometimes one after another.
Defining climate trends isn’t easy
Because climate is so variable, we need long periods of data to be able to predict trends. Anyone who predicts a trend on a short period generally doesn’t know what they are doing. The length of time needed depends on what you’re measuring, but to say the world is getting warmer, or not, requires decades of data – shorter periods may give a wrong impression.
Models not graphs
A graph gives a good picture, but it can give the wrong impression, and it doesn’t explain causes. Scientists use computer models based on known physical laws to make their predictions and to define causes. As computers get faster and models get better, and as we gather more data, the predictions get better. But they aren’t infallible, just probably right within certain limits of accuracy.
The models that predict global warming are coming true
All but a handful of climate scientists accept the models and the conclusion that extroardinarily rapid increases in atmospheric carbon dioxide caused by human activity (predominately burning of fossil fuels) has caused unprecedented global warming that will (among other things) melt polar ice, raise sea levels, increase storm surges, change weather patterns and have disastrous consequences for many nations – e.g. low lying coastal land and already dry North Africa are going to be badly affected. The model predictions haven’t been perfect, but they are getting better, and they all point in the one direction.
The usual suspects
Opposition to the consensus scientific view comes, in the main, from companies earning profits from fossil fuels (there is evidence that they are using similar tactics to those once used by tobacco companies to distort the truth about smoking and lung cancer) and media magnate Rupert Murdoch (e.g. the Murdoch press in Australia uses anecdotes and snide comments about occasional weather anomalies, which are expected, rather than serous analysis of scientific data). These diehards are compromising the lives of billions of people by their often dishonest opposition to positive action on climate change.
The latest news
NASA updates data on world climate every year. Here is a graph of their latest global temperature data, from 1880 to 2014. This graph presents annual average temperature expressed as a deviation from the 1951-80 mean. (Note that different data sources give slightly different figures because there are many ways to calculate an average temperature across the entire globe. As long as the calculation is consistent, the data will be meaningful.)
What do we see?
This graph illustrates many of the facts about climate change.
Average annual temperature varies a lot
It is easy to see the graph jumps up and down a lot. A cooler year doesn’t change the fact that temperatures are rising overall, and all the hottest years on record are recent. And 2014 was the hottest of all.
Trends over several decades
Since 1880, there appear to have been several different trends – a cooling trend (1880-1910), a warming trend (1910-1944), generally constant (1945-1970), then a sharp rise (since 1970). There may be a slightly slowing of the rising temperatures since 2000, but it is too soon to know.
It’s way hotter than it was a century ago
In the last century, average global temperatures have risen more than a degree Celsius. Scientists say this is significant, and is already having significant effects on the earth.
It’s really happening
We should trust the scientists and their models. But the graph is clear. Just look at it. Despite what the sceptics say, the world really is warming, our weather is changing, and the effects are becoming serious.
Christians and climate change
For some reason, many christians are sceptical about climate change. I’m not sure why.
But the data is clear. We don’t know how long people will be living on this planet, but we cannot presume to know that God is proposing to end the world any time soon.
Caring for God’s world, and especially for vulnerable people in North Africa, Bangladesh, Pacific Islands, Nepal and many other places requires us to be willing to act, even if these is a cost, and to support politicians who will act.
Photo: Flickr Creative Commons