In Earth's recent history, seasonal and regional differences in weather have been considerable.
But in the 1980s scientists noticed something irregular was happening to our climate.
Average global temperatures were rising.
This trend became known as global warming.
The Earth's climate has changed naturally many times in the planet's history.
But this change is different.
There is evidence to suggest a close link between temperature increase and greenhouse gas emissions.
Most scientists now agree that human pollution is at least partly to blame.
Some estimates claim that Earth's temperature could rise by 5.8°C in the next 100 years, while some believe the increase will be much more gradual.
But whatever the timescale, the implications could be serious and could even be catastrophic.
The minimum predicted rise is 1.4°C over the next 100 years.
That's more than double the increase we've seen over the last 100 years.
Future increases in temperature will completely change our climate, increasing extreme events.
There will be droughts, floods, and severe storms all around the world.
The most extreme predicted temperature increase would cause the ice caps to melt, producing a sea level rise of up to 90cm, making many coastal areas completely uninhabitable.
To avert these catastrophic changes to Earth's climate and ecosystems, we need to freeze greenhouse gas emissions.
Yet global energy use is likely to explode, as developing nations strive to catch up with the rest of the world.
This means by 2050 we could double the amount of greenhouse gases we emit around the world.
Unless we make significant changes now, global warming is set to continue - and worsen - with devastating effects.