Are humans one of the main causes of Global Warming?

We produce massive amounts of carbon dioxide, which is a green house gas, for one.

Well, that’s the rub. We know that human activity is a cause. But we also know that the earth goes through regular warm and cool cycles. So the proportion of human cause vs. natural cause is hotly debated.

Yeah that’s exactly what I want to know. Human Cause vs. natural cause. Perfect.
But I want to know the human side.

No, prove me wrong.
Yes, prove me wrong.

http://www.aph.gov.au/library/pubs/climatechange/whyclimate/human/human.htm

If you are considering the 100% cause of global warming to be the addition of CO2 to the atmosphere then….

1) the Earth goes through regular “warming” periods in which the CO2 in the atmosphere naturally rises at an exponential rate, until it caps out and then drops dramatically. The Earth is in fact at one of these warming periods right now.

2) However, during these warming periods it’s not abnormal for the CO2 in the atmosphere anywhere on the planet to shoot up into the mid-upper 300ppm range (during the calmer periods it rests 150–250 range). Right now, and for the first time in recorded history, that rate is over 400 ppm on average worldwide. Human intervention is undeniably the cause for this unprecedented rise.

3) Thus combining points 1 and 2, humans are not technically the largest cause of global warming… We just might be causing it to be a lot worse than it normally is.

For more information, please learn about the vostok ice cores.

http://www.daviesand.com/Choices/Precautionary_Planning/New_Data/ (I learned about all this in college, but this is just a quick link off google)

Well, just talking about CO2 we produce about 29 billion tons annually which is actually a pretty small amount but it turns out that when added to what the earth produces it’s more than the natural carbon cycle can absorb leaving the remainder of what we produce in the atmosphere.

Here‘s a chart that helps show the sources for some of the human produced greenhouse gases.

Are we the “main” cause? Possibly. But our actions do seem to be heavily contributing to knocking the natural greenhouse/carbon cycle as far out of whack as it is. Or, another way to say it is, restraining our activities would give the cycle more “room to breath”.

The overwhelming weight of scientific evidence is that humans are responsible for the majority of climatic change since the middle of last century. No explanation, other than the increased concentration of greenhouse gases in the atmophere, as caused by us, can better account for these recent changes.

See here:

http://www.skepticalscience.com/

And watch this:

http://earththeoperatorsmanual.com/broadcast_info

The heat emission generated from the heads of ginger people are cause alone to point the finger of blame squarely at their door ;¬}

FACT: We burn fossil fuels
FACT: Burning fossil fuels releases CO2 into the atmosphere
FACT: Increased concentrations of CO2 in the atmosphere leads to warming of the planet.

The only unknowns are how much and how quickly.

Then there is also the fact that humanity has destroyed massive amounts of forests, severely diminishing nature’s ability to convert CO2 into oxygen.

And it is not just CO2. Humans also have pumped and are pumping massive amounts of methane into the atmosphere (mass farming), which is an even more potent greenhouse gas than CO2.
In Russia, there are fields that contain huge amounts of methane bound under a layer of ice. The concentration is so high that you can puncture the ice and get yourself a nice big flame. Those fields are in the process of melting. Can you guess what will happen if all that methane is released?

First, to answer your question. Human activity is solely responsible for global warming being a problem we need to solve. As @HungryGuy & @tedd noted, the Earth routinely goes long glacial periods interspersed by shorter interglacials where the temperatures moderateglaciers recede. We are in an interglacial now, and it started about 10,000 years ago.

Atmospheric CO2 levels track with these temperature fluctuations. But in the last 500 million year, atmospheric CO2 has peaked at about 300 PPM. It is now approaching 400 PPM and ramping up.

To your other question, how much is human activity and how much is natural. This is one of the tools the #37 trillion a year fossil fuel industry uses to foster junk science in order to protect their profits. The truth is that most of the CO2 that goes into the atmosphere comes from natural sources. Animal respiration, decay of dead animal and plant matter, naturally occurring forest fires and volcanoes all put CO2 into the air, much more than humans add. However, the earth’s natural CO2 absorption systems, oceans, rain and plants, remove this CO2 so it doesn’t build up unduly.

Final question. What arte humans doing to cause CO2 buildup. We are brining fossil fuels and plant material, adding an additional 29 gigatons per year and that rate is constantly ramping up. And we are rapidly deforesting the Earth, removing one of the natural sinks that pull CO2 out of the atmosphere. CO2 in the atmosphere has a natural half like of roughly 7 to 10 years. But when we are pumping in additional CO2 the the Earth’s natural sinks can’t absorb, what we add has no half life. It stays and accumulates year by year.