Actually, I have thought about this. This is the source of my hangup. In recent history, we have hourly temp data. We don't have that granular of data even 10,000 years ago. I assume that's why your graph is logarithmic. Our temp measurements in the past are neither temporally precise nor close enough together to even compare with today's temp spikes. Do we have annual measurements 350,000 years ago? Measurements to the decade? The century? Are the measurements close enough together to even register a spike like today? My main question is this: how can we compare rates of change today to rates of change in the past when we don't have the past data? *I could totally be wrong about our past measurements...maybe they ARE more granular and precise than I think.
Again, do we have measurements precise to 1000 year intervals?
This chart is limited to about 1500 years. According to your long term chart, it does appear that there are massive spikes and drops in temp. But I don't really trust those because again, what granularity are we talking about with data points?
I'm not trying to argue man made climate change. I just want to know from a logical/data/math perspective, do we have the data to say things like "this rate of change has never happened before".
Ok those are all good questions, so let me make a couple of points.
First and to clarify, the questions we want to answer are:
- Is the Earth warming
- Is it caused by human activity
- Is the change in climate bad for us
To answer all of those questions we actually don’t need to know what the Earths climate has done in the past, (although it does help).
Using the energy budget which I described earlier in the thread, to measure the incoming vs outgoing energy from year to year we can determine whether Earth is gaining energy.
It is, therefore on average the temperature is increasing. We have satellites that provide direct evidence of the this energy imbalance.
When answering why the earth is warming our energy budget can help their too. By looking at where the energy accumulates we can corroborate our assumption that the earth is warming and we can find the mechanism by which it’s warming.
The energy budget over the last couple of decades shows
- Solar output is neutral or slightly negative
- Land temperatures have increased
- Ocean heat content has increased by a staggering amount (3X10^23 joules)
- Surface temperatures have increased by 1-1.5F
- Lower to mid troposphere temperatures have increased
- Stratosphere temperatures have decreased.
This shows that the sun is not the cause of the warming, if anything we should be slightly cooling. It shows the energy is reaching the surface. The warming lower atmosphere and cooling upper atmosphere shows that the energy leaving the earth is not making it all the way back to space and the suggest greenhouse gasses.
We have been measuring the constituent gasses of the atmosphere for decades. Greenhouse gasses are increasing giving a direct causal mechanism for the warming.
But the increases in greenhouse gasses could be natural. However as has been mentioned the amount of radioactive carbon is different between new carbon and old fossil fuel carbon. So as the ratio changes between new and old carbon in the atmosphere we compare it to the amount of fossil fuels we know we’ve burned and it’s obvious the increase in GHGs is man made.
So finally can we tell that the warming is dangerous to us without knowing what Earths climate was like in the past? The answer is unequivocally yes.
Our farms and crops are setup for climates they’ve been created for. The climate of the last 100 years. When the climate changes the crops and the locations of the farms will have to change increasing costs and reducing output during the change.
Now some places will benefit from the warming climate and some plants may benefit a bit from the extra CO2 provided more water, nitrogen, fertilizer and nutrients are available. But it will all cost a lot of money, effort and time.
Warming oceans and atmosphere means increasing sea level rise. About 650 million people live on the coasts along with all port cities. Sea level rise will cost trillions in mitigation in the coming decades. As an example Miami Beach, a city of 90,000 is spending half a billion over the next several years to combat tidal flooding from sea level rise. Multiply that by all the coastal cities.
Oceans acidify as CO2 increases. This coupled with runoff and overfishing puts pressure on the ocean ecosystem that billions of people rely on for food and underpins our entire ecosystem.
Fossil fuel companies have enough reserves already identified to raise the amount of CO2 to well over 2000PPM if it all gets burned - which is what they intend. The cost of burning all of these fossil fuels will almost certainly outway the benefit of burning them in the first place. So it’s important to use them as bootstraps now to get us onto carbon neutral/free power before the costs becomes that exorbitant.
Well this ran longer than I wanted. So I’m stopping here.
I’ll comeback to your points about the historical temperature record later.
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