Ice core carbon dioxide levels time line?

Answer 1

Ice core samples, by definition, must be taken on polar ice caps, because that's the only place where ice stays frozen year-round, and the only place where it can accumulate year after year. But polar ice caps are surrounded by millions of square miles of near-freezing water. Water absorbs carbon dioxide. In fact, the solubility of carbon dioxide in water increases, geometrically, as water temperature decreases, reaching maximum solubility at the freezing point. Of course, this is also true of nitrogen and oxygen, the two primary components of air. However, carbon dioxide is much more soluble than either of those at all temperatures. At the freezing point, carbon dioxide is 30 times more soluble than oxygen and 70 times more soluble than nitrogen. Now, if you have all this very cold, nearly freezing water surrounding these ice caps, sucking up carbon dioxide out of the polar atmosphere, at nearly the highest possible rate, 30 times faster than oxygen, and 70 times faster than nitrogen, doesn't it stand to reason that the air that remains might just have a lot less carbon dioxide in it than the atmosphere across the rest of the planet? This is the air that is being trapped in air bubbles, to be preserved in ice core samples. And it is not representative of the atmosphere as a whole.

There is more to this answer.

CO2 will also diffuse through the ice at a set rate and the effect over time will be that the CO2 concentration will be a function of the vapor pressure of the CO2 in the trapped air, and the rate of diffusion of the CO2 through the ice. After a sufficiently long period under pressure it would be expected to stabilize at a level below that in the original bubbles. It is probable that agreement of the CO2 levels in ice cores is due to this diffusion function over time under particular pressures, rather than the original percentage of CO2 in the trapped air.

Answer 2

For the past 20 million years CO2 levels ranged between 200 and 300 parts per million (ppm) of our atmosphere.

For the past 800,000 years the average CO2 concentration gradually varied between 250 and 290 ppm.

4000 BCE 260 ppm

3000 BCE 260

1000 BCE 280

1 AD 280

1700 280

1900 290

1950 300

1960 316

1970 325

1980 338

1990 354

2000 370

2010 388

Projected:

2020 415

2030 444

2040 474

2050 504

2080 600

2100 650

Answer 3

Ice core records can provide a historical timeline of carbon dioxide levels in the atmosphere by analyzing air bubbles trapped in the ice. These records show that atmospheric CO2 levels have fluctuated over the past 800,000 years, with levels ranging between 180 and 300 parts per million during ice ages and interglacial periods. However, in recent years, CO2 levels have spiked to over 400 parts per million due to human activities like burning fossil fuels.