In chapter 2 of this summer’s “Red Team” report on climate for the United States Department of Energy, the research team looked at the direct impact of CO2 on the environment, namely global greening and effects on ocean alkalinity. In chapter 3 they move on to indirect effects, namely climate impacts. They start by noting that the climate has changed all through Earth’s history, driven by factors such as oceanic cycles, orbital changes, solar variations, volcanoes and more. Humans are also changing the composition of the atmosphere by emitting CO2 and aerosols. This changes the balance of energy coming in from the sun and going out through radiation at the top of the atmosphere. This balance is, according to the IPCC, called “radiative forcing”, and the DOE report presents the numbers as they are shown in the IPCC reports. But they also point out something often left out: changes in radiative forcing due to greenhouse gases, as measured by the IPCC, are very small, indeed are below the measurement limits of modern satellites. So we’ve been given error bars as proof positive, which is not how science works.
On page 12 of their report, the DOE team reproduce the IPCC’s estimates of how much each type of radiative forcing has changed since 1750. The IPCC says the sun has added very little to forcing, and therefore warming, although the DOE team point out that this is because they pick the solar reconstructions that imply very little solar brightening since the 1700s. There are other reconstructions out there that claim the sun has brightened somewhat. They also refer to the ACRIM gap controversy, a topic we covered in our video on the topic, which involves how to calibrate readings to cover a gap in the satellite record of solar energy measures due to the Space Shuttle Challenger explosion in 1986, adding to the debate about whether the sun has contributed to warming in recent decades. The DOE report doesn’t express a view on the topic, it just mentions it.
The IPCC tally of radiative forcing includes the positive (warming) effect of CO2 and other greenhouse gases and the supposed cooling effect of aerosols (i.e. particulate pollution). It all adds up to about a 3 Watts per square meter increase since 1750. Which sounds like a lot, and looks like a lot in the way it is usually graphed. So they add some helpful context:
“However, this is still only about 1 percent of the unperturbed radiation flows, making it a challenge to isolate the effects of anthropogenic forcing; state-of-the-art satellite estimates of global radiative energy flows are only accurate to a few W/m2.”
This figure, of about one percent of the total energy flow in and out of the climate system in Watts per square meter due to solar heating and planetary cooling, is simply too small to be confident about our measurements even with modern satellites. Funny we haven’t been told of it before.
It’s especially important context because the report next discusses the change in atmospheric CO2 since 1958. Those charts can look scary the way the axis is always compressed, but the DOE team drew it differently, starting at zero:
The blue squiggly line is the CO2 level, and it’s squiggly because atmospheric CO2 has an annual cycle, dipping in the northern hemisphere spring and summer as plants sprout and absorb more, and rebounding in fall and winter as they die and decay. The green and grey dotted lines are the levels below which plants start dying not as part of a cycle where they sprout again in spring but as part of extinction (plants are grouped by biologists into C3 and C4 categories with the latter, more recent evolutionarily, better suited to the ominous CO2 famine that has gripped the Earth for tens of millions of years). The purple arrow shows how far CO2 fell in the depths of the last glaciation around 20,000 years ago, when it got perilously close to a level where plants start dying off en masse and permanently.
The rate at which the blue line will continue rising will depend on future CO2 emissions, which brings up the business of IPCC scenarios. We’ll look at their treatment of that issue next week.
It seems obvious to a degree ,that anyone above moron level must understand, that increased Solar Activity will Warm the Planet yet everyone,including CDN makes little of the fact that we have 1200 years of observations which show that we are unquestionably in a Solar Maximum. Just Google that and it slaps you in the face.