If there were no people on earth, would it still have global warming?

Answer 1

First a correction on Trevor's answer. WE are not Homo Erectus. We are Homo Sapiens. We have been around for about 200,000 years and have had very little to do with the climate IMO. The earth has been warming and cooling for billions of years. It is not static and those that think it is are ignorant or pushing an agenda. We are currently in an ice age with periods of glaciation and interglacial periods in a 100,000 year cycle. The last period of glaciation ended about 10,000 years ago. Since then there have been natural warming and cooling trends. The GW alarmist pretend to know that the latest warming trend is caused by man but they are ignorant enough to not understand their true ignorance of the facts.

Answer 2

VERY SHORT ANSWER.

Yes.


NOT SO SHORT ANSWER

The planet is a little over four and a half billion years old, homo erectus (us) have been around in one form or another for about two million years and have been contributing significantly to global warming for about 150 years. If we condense these times into a period of a single year then the planet is a year old, we've been around since 6pm on 31st December and we started contributing to global warming at one second before midnight.

In all this other massive period of time the climate has always done it's own thing - either warming or cooling but never static. This is because both Earth and the Sun go through a series of cycles, some lead to warming, some lead to cooling. The way they interact determines whether Earth warms or cools.

In the past there have been at least four full ice age cycles that we know of (there will almost certainly have been more). During these cycles the world warms to about 35°C and drops to about 5°C making the planet a very different place indeed from that which it is now. For comparison purposes the average global temperature now is 15°C, so we're more towards the cool side of things.

These cycles last approx 125 million years and although it may seem strange, in the larger scheme of things the planet is heading deeper into an ice age and has been for just over 50 million years.

It gets a bit more complicated, within these long term cycles are more cycles, and within them are more cycles, and more and more. It get's confusing.

If we look at the period in time that is often associated with global warming we're looking at the most at the last 200 years. If nature had been left to do it's own thing this is what we would have observed: Up until about 100 years ago there was a period of fluctuating warming and cooling, then for the next 50 years the planet warmed quite a bit (approx 0.3°C) before levelling off. For the last 30 years temps should have fallen slightly.

Turning now to the future and having stripped away the human contribution to global warming, what we'd observe in the immediate future is a slight warming before levelling off again. Longer term the trend would be one of upward temperatures, rising at a rate of approx 1°C in 10,000 years.

That's a summary of the climate had humans not been around. The reality of course is very different and most notably so during the last 50 years. During this time temps should have fallen a little, in fact they've risen faster than has ever before been known.

Answer 3

Absolutely yes. All one has to do is look at the geologic history of this planet. About every 15,000 we have an Ice Age followed by guess what ??? Global Warming that melts the glaciers, frees up the ice covered land masses etc.... Eventually this period of Global warming ends and the cycle begins again with another ice age which by the way we are currently past due for.

Answer 4

Yes there would still be warming and cooling.

If you mean would it still be warming right now, it's hard to say exactly because there's a bit of conflicting data regarding the recent output of the Sun. One measurement says it's been slightly warming while another says it's been slightly cooling:

http://tamino.wordpress.com/2007/07/24/pmod-vs-acrim/

Other than human influence, the Sun is the largest contributor to climate change.

http://en.wikipedia.org/wiki/Image:Climate_Change_Attribution.png

Either way the Earth would not be experiencing very much warming or cooling right now without human greenhouse gas emissions.

Answer 5

Sure we would. The Earth has entered and exited into several ice ages since the beginning of time without man being around to cause it.

To say that these ice ages were "natural" but the slight warming we see today is not, is scientific folly.

The climate always changes, there is no such thing as a static climate. If the climate is not cooling, it's warming. These are the only two possibilities.

Answer 6

Yes. Theres Global Warming going on on MARS right now so obviously the sun has something to do with the phenomenon. Humanity is just making it worse.

Answer 7

Yes, and global cooling.

There would still be hurricanes, droughts, hail, melting ice sheets, hot summers, etc. etc. etc.

All without people being around.

The problem with global warming is that it's buried in political and economic agenda. The agendas of scientist and politicians causes distortions and fraudulent data and poor conclusions about the data.

Global warming is big money. And it takes a lot of money and regulations to fix problems you know.

Answer 8

Yes, the SUN has increased it's energy level by as much as 2 watts meter^2 over the last hundred years. The Pacific Decadal Oscillation PDO entered into to it's warm phase starting in the mid 1970's. Those two variables will definitely cause warming, with or without an industrialized human population, adding to the trace gases in the atmosphere.

Answer 9

The world has always heated up and cooled down, but there would certainly be less air pollution and emissions of certain gases without human activity.
Even if humans didn't cause global warming, they do cause the planet to be uninhabitable.

Answer 10

During the Late Paleocene Thermal Maximum (LPTM), about 50 million years ago sea surface temperatures in the high Arctic were 23C (73F) There was no permanent ice anywhere on the planet. Most of the land, even at extreme latitudes, was covered by by what today we would call tropical forest. This was long before there were any humans, right at the start of mammal evolution.