what is the cause of climate change? (mans activities or natural cycles)?

Global warming, in it’s broader context, is the term we use to describe the warming that occurs due to the greenhouse gases in the atmosphere retaining heat. Without these gases there would be no global warming at all, either natural or manmade.

If such a scenario existed then Earth would lose it’s ‘insulation’ and all our heat would be lost into space.

The average global temperature would be –18°C – too cold for life to have evolved. Given that the Moon and Earth are essentially the same distance from the Sun, we’d see temperatures akin to those of our lunar neighbour. It’s thanks to our atmosphere and the greenhouse gases within it that we have a habitable planet.

Since the birth of our planet the have always been greenhouse gases in the atmosphere and the levels of these have fluctuated wildly. Tied to these changes have been changes in Earth’s climate.

However, something that is too often overlooked is the speed of these natural changes. They don’t take a few years (as is the case with the current warming), they take thousands and millions of years. What we’re seeing now has no parallel in nature, in fact, there’s never been anything that’s even remotely close to the rate at which the climate is now changing.

It’s all down to those greenhouse gases. For at least 15 million years the amount of these gases in the atmosphere was relatively stable and remained at between 180 and 290 parts per million by volume (0.018% to 0.029%).

In just 100 years the amount of greenhouse gases produced by human activities has been such that levels in the atmosphere have risen to 394 ppmv. That’s as much rise in 100 years as nature managed in 15 million years.

Given that there has been such a huge increase then it’s inevitable that more heat is going to be retained in the atmosphere. It’s actually a consequence of the laws of physics that this will happen and no matter how inconvenient it may be, and no matter how vehemently some people may deny that we’re altering the climate, there’s no escaping from the laws of physics.

If we apply some numbers – prior to the onset of industrialisation there used to be 1.4 trillion tons of CO2 in the atmosphere, today there’s 2.1 trillion tons – a 50% increase, most of which is carbon dioxide.

Because the relationship between greenhouse gases and temperature isn’t a linear one, this 50% increase in greenhouse gas concentrations doesn’t mean a 50% increase in temperature (either relative or absolute). Essentially, for each additional unit of greenhouse gas that’s added to the atmosphere the amount of warming it causes gets smaller.

The naturally occurring gases provide us with some 33°C of warmth, the ones we’ve released have added just 1°C. A small amount by comparison but a significant one all the same. Weather and climate are finely balanced, it doesn’t require much of a change to disrupt them.

It’s no surprise therefore that we’ve witnessed very significant changes in the global weather patterns in the last few decades, something that will inevitably continue into the future.

If you say natural cycles, you have to explain those cycles. It is not the cycles of the earth's tilt and orbit, they would be causing cooling over the past 6,000 years. It would not be "coming out of an ice age" because that is CO2 dependent and the new CO2 is not natural. It is not from the sun because if it were then days would be warming more than nights, and the greatest warming is nighttime minimums.

There is no natural cycle that fits with the observed warming. In natural cycles, the oceans give off more CO2 as they warm but we now have the oceans absorbing net CO2 as they warm -- that absolutely never happens during natural cycles.

If this is a science class, then you cannot explain global warming by natural cycles. There just is none that would be causing warming now and fitting what is happening. You have to explain why the oceans are absorbing CO2 as they warm, why the nights are warming more than days, and why the stratosphere is cooling while the troposphere cools. If you have some explanation for that that is not dependent on human emissions of CO2 then you would be waay ahead every of every climate researcher with multiple PHDs and decades of research. You had better by extraodinarily smart are stick to what the science supports which is that global warming is from human activities.

There are a number of natural factors responsible for climate change. Some of the more prominent ones are continental drift, volcanoes, ocean currents, the earth's tilt, and comets and meteorites. Let's look at them in a little detail.

See the following website for a good review: http://edugreen.teri.res.in/explore/climate/causes...

The causes of climate change can be classified as human and natural causes. Natural causes include volcanic eruptions, ocean current and solar variations. Human causes include deforestation and pollution.

what climate change? Where in the world is this supposed to be happening and by how much?

Proof humans are responsible for global warming comes when we look at the frequencies of radiation associated with the warming. First we look at the frequencies associated with CO2 absorption. To do this we can go to the following page and select the following options.

http://spectralcalc.com/spectral_browser/db_intens...

1. Select 'Group by Molecule' if it is not already selected.

2. Select the following in 'Spectral Range': Units - wavenumber, Lower limit - 400cm^-1, Upper limit - 1400cm^-1 (This is the approximate area for the black body radiation curve of the Earth)

3. Select the following in 'Options': 'scale by atmospheric abundance', Atmosphere - standard, Scale - linear, Symbols - sticks

4. From the select menu under 'Species' select the following gasses: H2O, CO2, O3, CH4, N2O (These are the five most prominent greenhouse gasses.)

After you hit the plot button you can see just how much an effect each gas has as it pertains to it's atmospheric abundance. As you can see the core of the CO2 band is at about 667cm^-1. Now what happens when we increase the amount of CO2 in the atmosphere? To find out we look at a University level text book written by David Archer, a professor at the Department of The Geophysical Sciences at the University of Chicago. Chapter 4 of his book "Global Warming: Understanding the Forecast" deals with greenhouse gasses. If you scroll down to figure 4-5 near the bottom of the following page we can see that, while the middle of the CO2 absorption band remains relatively static after a certain concentration is reached the band does not get deeper but gets wider with increasing CO2 concentration.

http://forecast.uchicago.edu/archer.ch4.greenhouse...

Next we look at the changes in tropospheric, or lower atmospheric, radiation to see what is causing the current warming and if it is actually due to CO2. Griggs et al published a paper in 2006 that built upon their 2001 paper that did just that. If we look at the various graphs on the paper in the following link we see a range of measured frequencies from 700cm^-1, the right hand side of the CO2 absorption band and the point where we will see the most change if the increase is due to CO2, and 1200cm^-1. And, in fact, between the years 1970 and 2003, the study period, we see just that.

http://journals.ametsoc.org/doi/pdf/10.1175/JCLI42...

Now that we know the warming is due to increases in CO2 we need to find out where that additional CO2 is coming from. Historically during warming periods CO2 concentration has risen after temperatures increase due to what is known as Henry's Law, which states that at a constant temperature the amount of a given gas that dissolves in a given type and volume of liquid is directly proportional to the partial pressure of that gas in equilibrium with that liquid, and Le Chatelier's Principal, which states if a chemical system at equilibrium experiences a change in concentration, temperature, volume, or partial pressure, then the equilibrium shifts to counteract the imposed change and a new equilibrium is established. However, as we are currently using fossil fuels from what is known as the geological carbon cycle and pumping them back into what is known as the biological carbon cycle we are throwing that natural balance off. The result being an increase in the partial pressure, or weight, of that CO2 above the surface of the ocean and the oceans trying to maintain equilibrium. They are actually absorbing more CO2 than they are emitting during a warming period, as evidenced by their decreasing pH or acidification, which would not occur naturally.

http://www.bu-eh.org/uploads/Main/doney_ann_rev_pr...

For more proof we can look at measurements of increasing atmospheric CO2, which is currently rising at an average rate of 2 parts per million (ppm) or 15.6 billion tonnes annually, and estimates of human emissions, which stands at over 33.5 billion tonnes annually.

http://scrippsco2.ucsd.edu/data/in_situ_co2/monthl...

http://cdiac.ornl.gov/trends/emis/perlim_2009_2010...

The result of this being that the warming is mostly due to increasing CO2 and humans are responsible for it's increase.

The magnetic field is changing.

Trevor you're a effing liberal, grow the **** up

It is caused completly by the a virus, called " the human race".

both are responsible.

BOTH