On Friday Sept. 20, millions of people around the world protested to support action to slow down climate change and raise awareness about the magnitude of the problem.

What all these people have in common is that they all agree that climate change is real and we must do something about it. The evidence is overwhelming, the Earth is rapidly warming at a pace exceeding scientists' predictions. At this pace, in a decade or so, it would have real effects on life as we know it.

From what I heard, climate change deniers are not saying that there is no change happening, because clearly there is, but rather that this change is not man made. But what does this mean? Does it mean that what's happening is inevitable and so we should do nothing? Because, that's what it seems they are acting on.

I don't see why it's hard to believe that with all the population on Earth -- that is more than it ever was in history, and the level of industrialization which Earth has never experienced before -- it would have some effect on the climate. If science has proven that CO2 increases the temperature on Earth, then all the factories, pollution emitting vehicles and farms must have a big impact on the climate.

It's true that Earth goes through cycles of cooling and heating but these cycles happen over a long period of time. We have records for climate changes and for CO2 levels on Earth, that go back 800 thousand years. That's not the records we keep, but those are records kept in ice cores in Antarctica. According to these records the shortest time we had a rapid CO2 increase it happened within 1000 years and that was 12,000 years ago, around the last ice age. In comparison, the recent rise in CO2 concentration at the same level happened within 10 years! And it's continuing to rise.

Even if you refuse to believe that climate change is man-made, can we at least agree that our pollution is making it worse? If we can agree on that, then why not do something to reduce the problem.

Change is always difficult. Big companies that produce a lot of pollution, probably do not like to hear about climate change because it's not in their economic interests to reduce pollution. But there are other ways to do things that will be challenging and require changes to be made, but that doesn't necessarily mean that they will lose out entirely.

It's selfish and shortsighted to put short-term, in the grand scheme of things, financial gains ahead of people's future, even if it means ruining the planet for generations to come. I think the choice is either we start doing something to mitigate the problem for ourselves as we get older and our future generations, or continue like we're doing and suffer the consequences.