What’s warming Our Earth

July 2016 was the hottest July ever recorded, even June. In fact, every month going back to October 2015 has been the hottest since 1880.

It is hard to argue Earth isn’t heating up. But what is really warming the Earth?

The climate is an complex system, influenced by everything from our orbit  to gases  In our atmosphere to volcanoes. And when we say warmer, warmer compared to what.?

For most of history, temperature recorded looked like this Hot today hotter than yesterday and gonna be hotter tomorrow.

But with the development  of accurate thermometers (Anderus Celsius, Daniel Fahrenheit) and standardized temperature scales in the 1700’s we could get some real data, from ships crossing the Oceans, weather station around the world. But weather isn’t climate and a few temperature records do not complete  a global climate history. It wasn’t till mid 19^th century that we were collecting enough data in enough places to figure out an average temperature for the whole world, which is why US climate graphs starts in 1900’s while the UK’s go back in 1850’s.

There have been repeated tests and  efforts  and under various lenses to figure out the cause but none of this explains the cause.

It could be Human activity but it could be other things as well. Earth’s orbit is pretty wobbly. Our elliptical path around the Sun revolves like a Hula Hoop. Earth’s axis draws a circle every 21000 years, and wobbles back and forth every 42,000 years and all these affect  Earths climate.

But scientists understand these changes really well, and when they use them to predict climate change . They don’t see any.

The Sun provides almost all of Earths heat, dimming and brightening like a light bulb. For most of the last thousand years, when the Sun turned Up, temperatures rose on Earth, and when the sun dimmed , temperature fell. But in the past few decade, the sun’s been cooling slightly, yet Earth keeps getting hotter. Solar activity can’t explain today’s climate change. 

We know CO2 traps heat in the atmosphere and the last time Earth’s atmosphere’s CO2 level were this high Homo Sapiens didn’t exist.

But may be this CO2 is Earth’s fault?

When Volcanoes erupt they release tons of the stuff, like little magma powdered earth burps. Geologists measured how much, and it turns out humans release about a hundred times more CO2.

Volcanic activity can’t explain climate change.

Some things actually cool the Earth. Cutting down more trees makes Earth’s surface lighter, it reflects more light back into space. Clouds, pollutants, and aerosols in the atmosphere do the same thing, they make our atmosphere reflective, so less radiation gets in. Yet even these cooling effects getting stronger, Earth’s getting warmer.

But we know that greenhouse gases like CO2 and methane have skyrocketed, and when we calculate how temperatures should change based on those level, we finally see a rise. subtract the cooling from trees, and clouds and pollution and it matches more than a century of data.

What is normal Temperature?

The last time Earth’s temperature was below the the 20^th century average was December 1984.. Many of you have never seen  below average temperatures in your lifetime. July 2016 was the 379^th consecutive month and 40^th July in a row of above average temperatures.

In 1995, biologist Daniel Pauly coined the idea of “Shifting Baseline”, the idea that we evaluate change very differently depending on what we are comparing to. We know how hot earth has been over the past century and a half.

Scientists understand that Earth’s climate is  a complex puzzle, whose pieces affect one another in many ways. When we put those pieces  together the picture is clear.

Happy Reading