CO2 levels were between 240 and 280 ppm throughout the Holocene until the last century. That stability, and the resulting temperatures were important to the spread of humanity. Rapid changes are not good for humanity, and cooler weather would not be as good. 200 ppm is only a little above that of the ice ages. It would be colder than optimal for the growth of humanity. Staying within that range of 240 to 280 would have been best but we have shot out of that in recent years.
" ... The IPCC attributes 20th century global warming primarily to CO2 on the basis of climate modeling, claiming that the increase in solar activity during the 20th century was insufficient to cause the observed warming. Thus, it is claimed, CO2 is by default the only other possible cause of the warming [they don't know how to model ocean oscillations, so those are automatically & conveniently excluded as a cause].
However, climate models are programmed with solar forcing that is 5-13 times less than found by state-of-the-art solar activity reconstructions. ... "
" ... For example, the NASA-GISS climate model uses a solar forcing assumption which shows solar activity increased during the 20th century by only about 0.3 Watts per meter squared [W/m2]. Contemporary solar activity reconstructions, however, show that solar activity increased during the 20th century by 1.5 - 4 W/m2 or 5 - 13 times more than assumed by the NASA-GISS model. Reconstructed Total Solar Irradiance [TSI] shows an increase of ~ 4 W/m2 over the 20th century. Solar forcing based on these modern reconstructions is 1 - 2.6 times higher than the alleged forcing from increased greenhouse gases during the 20th century. In addition, climate models do not consider any of the multiple solar amplification mechanisms which have been described in the literature. Thus, the IPCC and others dismiss the role of the Sun in climate by conveniently assuming solar activity changed 5 - 13 times less than the research indicates.
In addition, since solar forcing was much higher than assumed by the models, this implies that CO2 forcing was significantly less than assumed by the models. ... "
There's more to the warming than they lead us to believe.
---------------------------------------...
About the IP CC Report confirming the previous statement :
" ...The Chapter 8 authors (a different group than the Chapter 7 authors) are explicit here that their claim about natural forcing being small compared to anthropogenic forcing is based on an analysis in which the only solar forcing that is taken into account is TSI. This can be verified from the radiative forcing table on page 8-39 where the only solar variable included in the IPCC’s computer models is seen to be “solar irradiance.”
The Chapter 8 premise that natural forcing is relatively small leads directly to the main conclusion of the entire report, stated in the first sentence of the Executive Summary (the very first sentence of the entire report): that advances since AR4 “further strengthen the basis for human activities being the primary driver in climate change” (p.1-2, lines 3-5). This headline conclusion is a direct descendant of the assumption that the only solar forcing is TSI, a claim that their own report no longer accepts.
The report still barely hints at the mountain of evidence for enhanced solar forcing, or the magnitude of the evidenced effect. Dozens of studies (section two here) have found between a .4 and .7 degree of correlation between solar activity and various climate indices, suggesting that solar activity “explains” in the statistical sense something like half of all past temperature change, very little of which could be explained by the very slight variation in TSI. At least the Chapter 7 team is now being explicit about what this evidence means: that some mechanism of enhanced solar forcing must be at work.
Solar activity was at historically high levels at least through the end of solar cycle 22 (1996), yet the IPCC is assuming that because this high level of solar forcing was roughly constant from 1950 until it fell off during solar cycle 23 it could not have caused post-1980 warming. In effect they are claiming that you can’t heat a pot of water by turning the burner to maximum and leaving it there, that you have to keep turning the flame up to get continued warming, an un-scientific absurdity. ... "
http://wattsupwiththat.com/2012/12/13/ip...
The IP CC keeps trying to tell the truth, but they just can't find the political will to do so. The whole premise of their existence depends on CO2 being the villain. No more funding if it is shown that CO2 warming has been insignificant and then people like Hey Dook (here at Y/A) will have to go back to sucking his thumb with one hand and holding his banky tightly to his head with his other hand while he contemplates a reason for his next out-cry.
The best would be little change from the 270 ppm at the start of the Industrial Revolution.
A substantial change in CO2 levels (we are way beyond substantial now), either up or down, is a problem because it will create significant changes in sea level (in either direction would be bad) and in the pH of the oceans, bad for marine life.
200ppm would be a disaster for life on this planet, about 800ppm would be nice, but we really have no say in co2 levels, these are determined by temperature, which in turn is determined by the Sun.
The problem is... there is no One Best Temperature. If CO2 had been at 400 for most of human history, and something we were doing was causing it to drop to 250, you would see a similar outcry, for similar reasons. Rapid climate changes destabilize ecosystems, considerably.
So, no, 200 wouldn't necessarily be an improvement. 250 would be.
No I don't think so, That is right on the threshold of what plants can manage any lower than that, and all C3 plants might die out, which is most plants, C4 plants like grasses would be okay though.
Personally I would like to see CO2 at a level of about 500 or 600ppm, our climate would just a little bit warmer, but it would be a lush and green world.
1.Paper airplanes now fly further.
2.Everyone will get a better mileage.
3.Higher elevations of biomes become inhabited by more vertebrates.
4. Insects of unusual size.
5. Everyone will feel more alert, active and happier.
6. We get sick less often.
7. We die younger.
So, there is a bad thing and a good thing.
200 might cause it to cool too quickly I say 250 We have to be careful because 6 degrees C lower and we would be in an ice age
absolutely we should have less CO2.
If Co2 was at 200 ppm would that be better because warming would be less?
