Evidence for climate change

Like clockwork, birds start singing outside my window at 00:30, every night! Each time I hear them I become instantly annoyed - birds singing at night is not calming for me. Instead, I sit there and wonder (after cursing a lot) the same things; Why are you up at this hour, it's night time?! Why have you not migrated to a warmer climate?

I then got to thinking, and with all the news lately about 2015 being the hottest year on record, I realised... They're staying here because it's (clearly) not that cold! The fact of the matter is, this is evidence that the world is warming. Winters here are much milder than they once where. The last time the world had a record cold year was back in 1909, over 100 years ago!

Since the millennium, 14 of the 16 'hottest on record' years have occurred, and it seems like each year is another new record. Warmer years have been recorded since the 1930's, with a few blips here and there, but the overall analysis of the past 150 years or so, shows a rise in temperature. It's not a coincidence that the warming started then- around the start of the 19th century is when the industrial revolution came to play. You know what that means! ... Carbon burning - a rise in CO₂ emissions and greenhouse gases. Scientists have been able to analyse bubbles trapped in ice from the Antarctic for the past 800,000 years; the results support the notion that the rise in CO₂ is human related. Natural cycles related to things such as volcanoes and ice ages allowed the CO₂ concentration in the atmosphere to fluctuate, anywhere between 170 parts per million (ppm) to 300ppm. However, since around 1850, the concentration has only been rising, with it's current level at 402ppm! The past 800,000 years has never had an increase above 300ppm!

Global annual average temperature measured over land and oceans. Red bars indicate temperatures above and blue bars indicate temperatures below the 1901-2000 average temperature. The black line shows atmospheric carbon dioxide concentration in parts per million.

It's clear that the rise of the industrial revolution brought a change not just to temperature but the amount of carbon dioxide we have in our atmosphere. It's no news to you that carbon dioxide is a greenhouse gas, and what do greenhouse gases do? They alter the natural process of the greenhouse effect - the Earths' atmosphere traps in some of the heat radiated from the Sun, allowing most of the rays to bounce off the Earth as infrared radiation. The build up of greenhouse gases acts like a cloud, which traps these 'bounced off' rays, making the atmosphere warmer.

There's ample evidence and data that supports the notion that greenhouse gases are contributing to the rise in global temperatures. But for those of you that aren't satisfied with that, and say 'but the Earth changes temperature all the time, look at the ice ages', I say, here's what other evidence there is that climate change IS happening:

-Global sea levels are rising. In the past 20 years, the average rate of increase is around 3.5mm/year. Before that, it was approximately 1.7mm/year since 1880. They can rise for two reasons, either the water is warming and therefore expanding, or, ice is melting ... which brings me onto ...
-The volume of glaciers around the world is declining. There's a lot of evidence of global glacial retreat. I can bet you that if you went to see one 10-20 years ago, it would look different now, larger perhaps.

A lot of imagery and info for you there, but this is just a snippet. Evidence for climate change is not hard to find, temperatures are changing and accelerating at worryingly rapid rates. Even if you still believe that warming isn't induced by humans, you cannot escape the evidence that warming is happening, and that's the problem. Things will start to get worse if it keeps warming (one of my previous blogs touches on what will likely happen). Before I know it, I'll have a tropical rain-forest outside my window and I'll never sleep!