The article referenced above, is a typical Climate Change alarmist straw man argument. The premise of the article is we have evidence that climate is changing. Well of course climate is changing. But the implied premise is that these changes are negative. The article is misleading in that it shows a cycle of warming and cooling over the last 300 thousand years. It claims that the cooler periods in this time span are ice ages. This is a false claim.
They are glacial periods in a single ice age which started about 5 million years ago. For most of the history of animal life on this planet CO2 levels have been anywhere from 2 to 5 times as high as they are today. The ideal CO2 level for promoting optimal plant growth is 5x what it is today. When CO2 drops to 180 ppm plants begin to die off rapidly. CO2 is not a pollutant it is essential to all life on the planet.
If you start taking temperature readings in December anywhere in the northern hemisphere and treat your reading history as if it were ALL of history then the spring thaw will seem very very alarming indeed. This is exactly the kind of thing that the hockey stick graph below does. It begins recording temperature estimates starting at about 1000 years ago but ignores the big picture. We will get to the big picture in a little bit but first lets look at another problem with this picture.
This hockey stick graph is the synthesis of many different ways of measuring temperature and CO2. Keep in mind we didn’t have an instrumental record until about the mid 1800s and the way we record those measurements has been in flux since then. When you change the way you measure something you tend to get changes in the measurements as well. While it is possible to try to stitch these systems together to form a longer trend, there tends to be a great deal of inaccuracy around inflection points at the place where they are stitched. Such as the inflection poins we see starting in the 1950s when they first started monitoring CO2 at Mauna Loa.
The above temperature reconstructions graph helps illustrate this. It shows all the different ways we have been measuring temperature and it is evident from examination that different methods yield different results. The results tend to correlate, but they are definitely different and stitching the data together is simply an opportunity to massage the data to create a narrative.
Now if you examine temperatures over a longer period of lets say 4 years (going back to our December example), then it becomes evident that the spring thaw is a normal part of a normal cycle. That is what the following graphs do by looking beyond our current ice age into the distant past as far back as 500 million years. To put things into perspective animal life came on to the scene about 300 million years ago.
Above we can readily see that not only are we currently in a period of abnormally cold weather which has been going on for about 5–10 million years, we are also in a period of abnormally low CO2 starting at about 50 million years ago.
This paper http://www.pnas.org/content/99/7/4167.full which was written before the Obama mafia politicized science, gives a much richer perspective. It shows how we measure CO2 beyond the history available via ice core data.
One thing to keep in mind is the definition of an ice age is that we have permanent polar ice caps. When climate change alarmists say our polar ice is melting what they fail to mention is that if we are not in an ice age then the polar ice will melt…all of it melts. Earth was never meant to remain in a perpetual ice age. And what we are beginning to find is that thanks to man made carbon, the earth is greening.
Climate change alarmists are working hard to leverage every known propaganda tactic on the books in order to maintain the hysteria. But at the end of the day this is nothing more than fear mongering.
More recently Climate Change alarmists have been saying yes for most of earths history things were warmer than they are today, but what we are doing is unprecedented. We have raised CO2 in a very short time so fast in fact that the earth cannot adapt. But this claim is on very shaky ground.
When you look at the ice core studies the temporal uncertainty of any reading up to about 11 thousand years ago is plus or minus 200 years. Beyond that the temporal uncertainty goes to plus or minus 2000 years. This means we do not actually have any way, based on ice core studies, to know exactly how fast carbon rises and falls in real time. Detecting rapid fluctuations over 50 or 100 years is simply not possible using ice core data.
The best we can do is to say that it looks like averaged over time, during the current ice age we find ourselves in, that CO2 does not seem to have changed as much as it has changed in the last 50 years. But to extrapolate from that observation a claim that our current rate of Co2 change is unprecedented, lacks any real evidence to back it up and is dishonest. Not only are we in an ice age which might be coming to an end, the data we have is naturally smoothed due to uncertainty. If for example in the past carbon had climbed 80 ppm in 50 years, and then dropped back down in the next 50 years we would not really have any way of detecting that. We don’t have any way of knowing if there has or has not been similar rates of change in earths past. I think on the whole given the balance of probabilities we are possibly seeing an unusually high rate of change in CO2 but I am not willing to take a leap of faith and say this is unprecedented, or worse to say it is catastrophic we simply don’t have evidence to support such claims.
One thing we do know from plant stomata studies is that 1) CO2 levels have historically fluctuated more wildly than the ice core studies would lead you to believe and 2) CO2 seems to follow temperature change rather than lead it. What does this mean? First the statement that our current CO2 level changes are unprecedented lacks credible supporting evidence. Second, the lag seems to imply that CO2 is not a driver for temperature change but a byproduct of temperature change. Whether this is indeed true or not remains to be seen but there is credible evidence to support this conclusion.
Climate change skeptics have a duty to continue to voice skepticism because the fear mongering is not healthy. Precious limited resources are being diverted from programs that actually make a difference into schemes to fight the end of an ice age which have no practical utility and are actually harmful to the earth.