is CO2 the cause of all this warming?

Not at all. The ice core is showing what happened in instances of natural warming. CO2 is always a feedback during natural warming, accelerating the warming. But we know that now the CO2 is coming first thus proving that now is different than natural warming.

How do we know that the CO2 is coming first and driving the warming? The most obvious way is because the oceans are acidifying; they are absorbing CO2 from the air. During natural warming, the increase in atmospheric CO2 comes out of the oceans as they warm. The CO2 is cycling in the wrong direction for natural warming. Another way we know is through the carbon isotopes in the air; they show that the CO2 increase is not from the ocean.

So, just follow the logic. During natural warming, the oceans always throw off CO2. Now the oceans are not throwing off CO2, they are absorbing it. Therefore, the warming cannot be natural.

This is just one of the things that is different from natural warming.

The simple answer is yes!

You are correct when you say the ice core records show that when temperatures increase, there is a delay before CO2 levels follow; this is due to what is known as a coupled feedback relationship between CO2 and temperature. Essentially, an increase in one, for whatever reason, will produce an increase in the other.

In the past, temperatures have increased as a result of changes in the earth's orbit; also angle of axial tilt (Milankovitch cycles), this increase causing a rise in CO2 levels, (from the warming oceans), which causes further warming, this continuing until equilibrium is restored. (The ice core record shows a cycle of ice ages and warmer periods, a cycle taking approx 100 000 years.)

The difference now is that there is no external cause for temperatures to rise; it is a consequence of the increase in CO2. The bad news is that much of the extra heat goes into warming the oceans which, in time, (from memory around 2050) will start to emmit CO2 rather than absorb it. As in the 'natural' warming we have had before, this extra CO2 will then cause further warming, causing extra CO2, etc etc, until equilibrium is restored.

I've tried to keep this as simple as I could; there are other factors too, but CO2 is the big one!

I've found this related question which has some excellent answers from the global warming proponents; especially the best answer, from a climate scientist.

http://answers.yahoo.com/question/index?qid=201005...

These guys know their stuff; I couldn't hope to improve on what they have written.

Actually, it's because the prior cycles of warming were not triggered initially by CO2, but instead by changes in solar output and the like.

CO2 can drive climate change, but it can also act as a feedback. A warmer ocean will tend to release stored CO2 (as long as there's not already so much CO2 in the air that the oceans are still absorbing it). (incidentally, this can be demonstrated with 2 bottles of soda. Open a cold soda, it won't fizz much unless it's been shaken recently. Open a warm soda, of the same size and type, and it will fizz a lot. The cold soda can hold more CO2 than the warm soda can.) So, if there's warming from, say, changes in the Earth's orbit, it will result in a CO2 release that will amplify that warming. That's how we can get relatively large changes in the Earth's temperature from relatively small changes in solar input, incidentally.

But, that also means that if you release CO2 into the atmosphere, in enough quantity that it increases the atmospheric concentration measurably, the Earth will begin to warm directly from the CO2, without another warming trigger.

you must specify timescales. We have warmed since the last ice age, but the last 100 years have been mostly due to increased human made CO2. The temperatures respond to the amount of CO2, even if the solar input has slightly decreased in the last decades.

There is a lag of about 800 years for the oceans to release more CO2 after initial warming, so there is a delayed feedback.

no CO2 is not the cause of all the warming. Other greenhouse gases such as methane and water vapour and the recovering ozone also have a hand. CO2, however, is the main one. As the planets warms more CO2 is released from the ocean. this heightens the warming. however the current release of CO2 via the burning of fossil fuels is not a consequence of a warming atmosphere and it is not natural. the ocean is currently decreasing in pH indicating an increased CO2 uptake. Human emissions account for 30gt annually while the atmosphere is increasing by 15gt annually. Half of the human emissions are being absorbed by the ocean. Look up ocean acidification.

To some extent warming does release more CO2....but the release is an 'effect' not the 'cause' of planetary warming. A 'warm' ocean will release CO2 and a thawing of tundra will release CO2 and methane. Before the early 1800 the CO2 load in the atmosphere was 286ppm more or less. This was the time when coal began to be burned for fuel as opposed to wood. As massive amounts of wood burning cleared forests, and more forests were cut for building material and ship building and opening farm land we experienced a coming together of several parts of a graph. The beginning of the industrial revolution in the early 1800's began the industrial use of coal, and by the end of the 19th century the use of 'rock oil' for illumination was common practice. Later in the early 20th century oil for automotive fuel rapidly increased the rate of CO2 production. Less forested land, more burning of fossil fuels and more people using fossil fuels added increasing tonnage of CO2 to the atmosphere. There's zero argument that CO2 isn't a greenhouse gas and the 'greenhouse effect' is established science. By 1950 the CO2 load reached 350ppm, the beginning of an era where more short wave energy from the sun became trapped in the atmosphere. To day we're at close to 400ppm. True, the 'atmosphere' has only warmed by a degree, but that's because the excess heat has gone to melt ice and warm seawater. Sea ice is far less now in area and not near as thick. Atomic submarines have been surfacing in the artic since the 1950's. The navy has kept track of ice thickness during various seasons. Winter ice is now thinner then summer ice was 50 years ago..that's a fact. The artic tundra around the 'edges' world wide now melts earlier, freezes later and thaws further north every decade...releasing massive amounts of CO2 and methane gas. We add 15ppm of CO2 every decade to our atmosphere and the isotope associated with that CO2 comes almost exclusively from burning fossil fuels. At 450ppm the oceans will be fully saturated with CO2 and long before that will begin to release more and more of it back into the atmosphere....the heat index will of course rise rapidly at that point as most of the ice will be gone along with it's heat sink effect. Ice cores of course track climate over geological time...millions of years. This current warming and CO2 accumulation has happened over 'historical' time..less than 200 years. ALL of the data, the science and the physics of atmosphere and heat confirm that human action has caused a rapid change and ongoing climate change....mainly illustrated by longer summers and shorter winters though not yet by appreciably 'hotter' surface temperatures. ..that come later!

>>>I believe it is what is causing this delay. as the earth warms, the ocean then slowly follows in temp, walla, releasing more CO2.

Yes, which is typically true of natural warming events and the glacial/interglacial cycle. Warming causes a release of CO2, as per changes in the vapor pressure of CO2 - however, that assumes that the relative pressure of CO2 is constant as temperature increases. If you increase the partial pressure of CO2 faster than you increase the temperature of the Earth's oceans, they will not emit net CO2, they will absorb net CO2. Such it is with the 40% increase in atmospheric CO2, which we observe with, as Baccheus pointed out, an acidifying ocean (more CO2 is being dissolved, not degassed).

As the oceans warm, their capability to absorb net CO2 will decrease, but currently they are not acting as a net source.

@Jerry Lee: Actually, they do. Here you go:

http://pubs.giss.nasa.gov/docs/1990/1990_Lorius_et...

http://www.sciencedirect.com/science/article/pii/S...

Its a fair question but I wonder if the answer really matters.

Even if the theory behind global warming is incorrect, it seems more certain that the world is running out of oil and a way to accommodate that situation is more efficient technology (blah blah blah) ..... which is essentially the same solution to reducing co2 levels in the world.

Part of it

CO2 is trapped in the ice so the more warming the more co2

So far as I know, the ice core records do *not* show CO2 lagging temperature change. Might help if you provide a reference.