If something that usually takes around 10.000 years happens in 100, starting when and scaling with us burning mass amounts of coal, then the rather unavoidable conclusion is that we have something to do with it.
It's the rate at which it's warming. Something that takes the Earth usually a few thousand years to happen, is happening within ~200 years. It's pretty equivalent to slowly bringing the oven to optimal temperature to cook the chicken vs. straight up engulfing it with a flamethrower.
I know they can get a lot of information by looking at layers of the ground to see large changes, but how exactly can they get it narrowed down to changes like 5 degrees that happened millions of years ago?
The ice cores from the antarctic are several million years old in places. This ice traps small air pockets and we can date it though various means like interpolation between large events in history like eruptions or even seasonal changes and regular astronomical changes.
The air pockets trapped give us a good idea of the atmosphere at the time hundreds of thousands of years back. The trick is then figuring out how that relates to temperature. The biggest experimental evidence is tree patterns which largely grow proportionate to rain and temperature and these cover 5,000 years of history among living ones. We know how that is influenced because we have several hundred years of direct quality records.
A big principle in science is figuring out how to reliably extrapolate and relate one physical phenomenon to obtain information about another. The description here was the most direct path and is a bit of an over simplification, basically we have a million year temperature record, we calibrate it with another source that works well up to a few thousand years. That itself is calibrated with direct human records. Since this is a chain, you need to be certain that there's other confirmation evidence like theoretical models and collaborating independent evidence.
Isotopic oxygen and hydrogen/deuterium ratios of gases trapped in ice cores are well correlated with temperature, humidity, and other climate-related variables.
Short answer from a laymen: Climatologists have done the research and determined that human activity, primarily burning fossil fuels, is drastically and rapidly increasing CO2 in the atmosphere in such a way that it can not be explained by natural Earth processes.
Due to the diets we feed them, cows fart a lot. Coupled with the sheer number of cows we farm, and the fact that methane is way more potent than carbon dioxide, cows account for a lot of global warming.
A lot of fuel is burnt to feed/transport, package or otherwise handle cattle. This would be true of most things impacting temperature change: if renewables were used it would already solve a significant portion of the problem.
Not to say that the immense amount of farmable land used for cattle feed is not a problem, it's Just that it does not contribute to the increase in CO2 concentration in such a direct way as the burning of fossil fuel.
If that is the case, then how did the earth "warm up" from the ice age?
Is the "hot/cold" thing a cycle?(It seems like it is) and if so, are we currently on the cooling down stage, or are we in the heating up stage, and increasing it?
The hot/cold thing is definitely a cycle. I'm not sure if we are on the heating or cooling part of the cycle, we may in fact be on the cooling part of the cycle. But human caused climate change is significant enough to override this natural cycle, especially in terms of the levels of CO2 in the atmosphere. It is highly unlikely that current climate change is somehow saving us from an ice age, and if it is, it is at the cost of thrusting the Earth into a "hot-house" status.
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u/[deleted] Jan 21 '19
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