The purpose of the previous two articles was to explain the scale of the human contribution to the carbon cycle and to point out that there is significant natural variation as well in the carbon cycle. The natural variation takes place year to year (ENSO cycle) and over the course of the year (Northern Hemisphere growing season). All of these variations make it impossible to know precisely how much natural carbon exits and enters the atmosphere naturally each year. What is known most accurately is how much carbon mankind is putting into the atmosphere.
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In the first part of this article I presented a broad overview of the carbon cycle. What it shows is that no matter how the data is analyzed, the human contribution to the flow of carbon into the atmosphere is relatively small (~4%) part of the total. This also means that the contribution to the […]
Posted March 13th, 2012. Add a comment
One of the few things that I have not covered before in depth is the carbon cycle. That is the path that carbon takes in and out of the atmosphere. For example, plants absorb CO2 from the atmosphere, but eventually that carbon will make it’s way back into the atmosphere. The flow of carbon from […]
Posted March 6th, 2012. 14 comments
In the ongoing global warming debate there is often a significant difference between the perception of what is going on with the Earth’s climate when compared to what is actually going on. There is no greater example of this than the summer temperatures in the Northern Hemisphere. Since summer has arrived (in practice at least) I am going to spend the summer going over recent research that shows that the modern period is not having unusually high summer temperatures.
The normal perception is that the summer temperatures are going to increase until they are much, much hotter than they have been in who knows how long. The reality is not even close to that perception. A recent study (Yi, Yu, 2011) is probably the highest resolution reconstruction using temperature and precipitation records from the region and then correlating to tree-ring data to create a high resolution reconstruction of the summer temperatures for North-Central China.
Posted June 6th, 2011. Add a comment
One of the most persistent and unscientific ideas out there is the one that all past climate change was caused by the level of CO2 in the atmosphere. The greatest example of this is the ongoing attempt to show that Antarctica today is covered in ice because 40 million years ago the level of CO2 in the atmosphere started to drop. There are many examples of this (DeConto, 2003, related search), but they are plentiful and they are all wrong.
I have previously written about the Antarctic Circumpolar Current (ACC) and the role that it played in changing Antarctica from a temperate climate (comparable to modern day Europe) to the ice locked landmass that it is today. The temperature difference between the equator and Antarctica is today twice what it was 40 million years ago.
Posted May 30th, 2011. 7 comments
Antarctica. It has an average temperature of -50 °C. There is enough ice locked up there to to increase the global sea levels by more than 70m. It has been that way for longer than mankind has existed. Antarctica has not always been such an inhospitable place though. In the time of the dinosaurs it was a temperature place. There were no glaciers, it was probably a pretty nice place to live.
When Antarctica started to freeze over 34 million years ago, the average temperature of the Earth was about 7 °C warmer than it is now. The freezing of Antarctica triggered one of the greatest climate change events ever recorded and the Earth has never been the same since that event. It also triggered the greatest extinction since the dinosaurs.
Posted April 13th, 2011. 9 comments
The last couple of days have been busy as readers have been driving some interesting discussions. On one page there was an unexpectedly interesting discussion about the Moon. It started with an error on my part that was corrected by a reader. It had to do with the predicted and actual surface temperature of the Moon. The impact of this could be significant, but that I simply don’t know yet, but the idea is an interesting one that will require some more information.
The predicted (blackbody) temperature of the Moon is 270K (-3°C). That is a warmer predicted temperature than the Earth has. This is because the Moon reflects away less energy than the Earth does. This predicted temperature is not the actual temperature of the Moon though. The Earth has a predicted temperature 254K (-19°C). It is warmer than that by 33 °C and the Greenhouse Effect is the common answer as to why the Earth is warmer than this. Since there is no atmosphere on the Moon, there cannot be a Greenhouse Effect, but the Moon is not the temperature that is predicted by the Stefen-Boltzmann equations. Most interesting is that it was much warmer during the night and cooler during the day than it was predicted to be.
Posted March 13th, 2011. 10 comments
One of my favorite aspects of writing articles for this website is I am constantly learning new things about the Earth and the climate. There are so many aspects to understand and there is always more to learn. Being open to new information is the true nature of the scientific method. It is also one that has broken down in the global warming debate because so few people are open to contrary findings.
The unexpected new piece of the puzzle that I stumbled across deals with the temperature of the land in different seasons. It focuses on the United States, but the behaviors described would apply to all regions of the Earth to some degree. Specifically it deals with how the temperature of the Earth itself varies at different depth over the course of the seasons. It is also a perfect example of how time lags show up in the climate cycles.
Posted March 10th, 2011. 10 comments
Dr. Hermann Harde from Helmut-Schmidt in Hamburg, Germany recently published a paper where he modeled the total impact of CO2 doubling for the Earth using the updated databases on the absorbance of greenhouse gases and water vapor in the Earth’s atmosphere. This approach was different from previous studies ( Myhre 1998, Hansen 1998) in that it accounted for more layers in the atmosphere and also accounted for overlapping absorbance bands. It also uses three major climate zones instead of two. This may not be critical as the results for two of the zones was very comparable, but it is still useful to see the results.
The big difference that I see is the added layers in the atmosphere. Radiative heat transfer is meaningless over large distances except in a vacuum which our atmosphere is not. So a model that is approaching the effects of the atmosphere is far more useful than one that treats it as only a couple of different interacting layers. This matters because it decreases the temperature gradients between the layers and as a result decreases the amount of heat that is transferred. As I have stated many times, nature does not like temperature gradients and as a result they do not last long in nature. I expect that as studies approach a model without layers that the effects of CO2 will decrease. The basis for that view is simply the amount of long wave (LW) energy that is absorbed by the atmosphere is already small which is why forcing is used in place of net heat transfers.
Posted March 8th, 2011. 4 comments
For those that believe that CO2 is the driving force of climate. I would like to show what happened to the Earth 120,000 years ago at the end of the Eemian Interglacial. That period is almost exactly what the projected world will be like if global warming happens. Understanding what it was like and what happened 120,000 years ago is helpful to know what the future holds for the Earth now.