Forums → WEPR → Global Warming
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How do you know the temperature was steady for 1800 years? the most effective global temperature readings didn't start until 1979.
As Firefly mentioned, there are ice core samples that can give us accurate readings. There are also many other methods of inferring paleoclimates. I just did this for my senior thesis, so I will give you a mouthful about sediment dating ;-)
As sediments deposit on land and in ocean basins, they build upon previous layers that have been deposited over time. This is called stratigraphy, an example of which you can see here:
Now, each one of these layers would represent a different time period. By taking a sediment core in an area, you can see these different layers in the sample and date them back to when they were deposited by which organisms are found in there. For example, in marine sediments you can look for organisms that used inorganic substances from the water column to precipitate their shells. One such type of organism, is called a foraminifera. They are tiny marine protists that precipitate their shells from the calcium carbonate and other substances found in the water. Here is what a fossil foraminifera looks like:
My study species is very charismatic, am I right? ;-) So, what we can do now that we have collected these fossils, is run them through a mass spectrometer. This will tell us the exact proportions of different elemental isotopes that were present in the shell, thus giving us an accurate record of the seawater chemistry at the time. Now, the important element we want to pay attention to here for inferring temperature is oxygen. Isotopes of O16 and O18 are found in seawater in specific proportions to each other, depending on the temperature of the atmosphere. This is because when we have large oceanic ice sheets, they are formed with the lighter oxygen isotope, leaving a larger amount of the heavier isotope in the water. So the proportions that we find of these give us a measurement of the ice cover of earth during that time, and a reading of the temperature once the proportions are entered into an equation.
So basically, taking fossil samples and breaking them down for their oxygen isotope proportions tells us what the temperature of the ocean and therefor atmosphere was at the time.
The fossils that I looked at ranged from about 21,000-31,000 years ago. And we can go much farther back than that. So yes, we do have an effective global temperature record going back very far in time.
Probably more than you wanted to know ;-P
I think the global warming is in only a period of time where the global temperature rises.
Well, this is where we should be correcting the use of the term. We really should not call this phenomenon 'global warming', but 'global climate change'. Yes, as an average, the overall temperature of the globe is rising. However, it is also decreasing in certain areas. Global climate change can be better characterized by more extreme conditions like with the seasons. For example, in certain areas summers will become much hotter, while in other areas winter will become harsher and colder. It all is resulting in an overall warming of the atmosphere, but it does not affect every part of the earth in the same manner.
pickleshack, here is a good visual representation of what you are talking about with CO2 and temperature correlations: 
C'mon Carlie, we all know the basic rule in statistics! Correlation is NOT causation.
You're right, it is not a direct causal effect. But it is a fact that increased CO2 in the atmosphere increases the amount of sunlight, and therefore heat, that is being reflected back to earth. This results in increased warming. And thus, ^CO2 --> ^Temp
So yep, in this case there is a pretty obvious relationship.
The section on the right is the one in question, you can click on it if its too big. If there are more greenhouse gases the amount of radiation reflected back to earth is higher.
So, what should we do about it? Tax breathing? Kill the real sources of CO2? Or ask the UN?
No no no, you are taking it way out of perspective. Thisisnotanalt had a good explanation when he said this:
The introduction of more emissions that are UNnatural is where the problem lies. The introduction of extra emissions is what throws the system off balance.
The biggest problem is that we are burning large amount of fossil fuels and putting other pollutants into the atmosphere. The earth has carbon sinks (plants, soils, deep sea sediments, etc.) where is stores CO2 and keeps the balance. But this added CO2 is more than the earth has the capacity to absorb and maintain equilibrium. Which is why it is building up in the atmosphere. These carbon sinks are trying to absorb more, but there is only so much that they can take. This is why certain phenomenon like ocean acidification are starting to happen. The increased absorption of CO2 into seawater is pushing the pH lower to more acidic values, which is causing negative effects for calcifying and other organisms who cannot cope with this pH change.
If you wanted to be realistic here, you would have said that we should make changes on how our industry filters and produce their emissions. Or how cars can be made to be more efficient and reduce emissions. How people can use CFLs as opposed to other light bulbs.
I understand you are trying to make a point ninjacube, but seriously, be reasonable. I apologize if I can't take your arguments seriously when you are so sarcastic about it. Come back with an actual scientific argument with better facts, and then perhaps you will make some sense.
The plants get rid of most, if not all of that.
It's actually the ocean that stores most of it ;-)
Goooo ocean!