There is still a debate with respect to what is causing global warming. Is it the result of man-made carbon dioxide being dumped into the atmosphere, or is it natural variations? The answer is yes. It is both.
Because it is both, the problem is far more pressing than if it were either one. Most of the publicity surrounding this issue takes one side or the other and then conveniently presents only evidence supporting their position. This only muddles the situation and leaves people with the feeling that real information isn’t available or that the problem is too complex to understand and therefore too complex to act on.
There are factors I am unaware of and some that I don’t fully understand, but I do understand more than what is generally being conveyed to the public, and I am completely convinced that there are both man-made and natural sources and that both are substantial.
On the natural side, people keep saying that the sun’s luminosity hasn’t changed significantly. This unfortunately is not accurate. If you look at only the light output in the visible spectrum, roughly 700nm red to 450 nm (violet), the output in this narrow spectral range is reasonably constant. However, if you look in the ultraviolet, the variably is considerable, and farther up the spectrum you look, the more significant is the variability.
During solar maximums, UV output is up considerably from times of solar minimums. This does impact our weather significantly. The sun has a 22 year magnetic cycle consisting of two cycles of build up of magnetic field, decline, reversal, buildup, and decline, so every 11 years there is a solar peak, and a solar minimum with the magnetic field being opposite of what it was previously.
But this cycle is itself irregular, there are longer term regular cycles upon which this cycle is superimposed that make some cycles more powerful than others, but there are also unexplained periods of exceptionally low and high activity.
During periods of high activity, Earth’s temperature increases, and during low activity, it decreases. Over the last 100 years, the overall trend has been an increase in solar activity temperature.
Contrary to popular belief and contrary to what we are told; solar flux and radio active decay within the Earth are not the only source of energy input. The Earth is also bathed in a constant bombardment of subatomic particles that we collectively refer to as cosmic rays. These rays consist of particles such as protons traveling at extremely high velocities, very close to the speed of light.
Distant cosmic events, matter being sucked into black holes, neutron stars colliding, ordinary stars being cannibalized by by a neutron star or black hole, these sorts of things generate cosmic rays. Cosmic rays affect our planets atmosphere in two ways, they can dump significant quantities of energy into our atmosphere and magnetosphere in short time frames, and they can affect cloud formation and precipitation which in turn affects the planets reflectivity as well as heat dissipation. We do not know why, but cosmic rays have been on the rise in recent years.
The heating of our planet by cosmic rays can be direct, as when particles collide with molecules in the atmosphere, and it can be indirect, increasing the natural flow of both ionospheric and telluric currents which then creates heat due to currents flowing through electrical resistance.
Most cosmic rays are intercepted by our planets magnetic field and then enter near the poles. However, our planets magnetic field has been declining over the past century (this is also part of a natural cycle) and as it declines, the point at which cosmic rays enter moves to lower latitudes. This affects the heat distribution as well as the weather. Where cosmic rays enter, those particles leaves ionized paths in their wake that serve as condensation points thus enhancing cloud formation at high altitudes.
Also on the rise is volcanic activity, particular under water volcanic activity. The volume of activity that exists is only recently being appreciated. The last global ocean survey counted more than 2 million undersea volcanoes. Granted, these aren’t all active, but it’s a number about 100x larger than what was previously believed to exist. The truth is that nobody really has an accurate assessment of just how much carbon dioxide volcanoes are contributing, but we know for sure it’s on the increase.
So, we’ve got solar activity that, although presently we’re in a solar minimum, is on the longer term on an increase. We have an unexplained increase in cosmic ray bombardment. We have a weakening of the Earth’s magnetic field. And we have an increase in volcanic activity. These all contribute to global warming and they are all completely out of our control.
Then we have the man-made side which is always oversimplified by the media as being solely a function of carbon dioxide production. Actually, it’s far more complex than that. Methane is several hundred times more potent than carbon dioxide gas, and until very recently it was on the rise. In the last few years, methane levels have leveled off and the thought is that methane has reached an equilibrium state where it is being broken down and oxidized into water and carbon dioxide in the upper atmosphere at a rate that matches the rate that it’s being generated. So that may suggest that greenhouse gases effect will not be rising as fast as it has been because methane is no longer rising. Water vapor is another potent greenhouse gas but it’s really a mixed bag, because while it prevents the escape of heat from the Earth, when it forms clouds, it also reflects heat and reduces heat input. Scientist do not have a firm understanding of whether the net effect is heating or cooling.
We also need to consider the effect that man has on the planets albedo, when we pave over a significant percentage of the planet with asphalt, build houses with dark roofs, we are affecting the planets reflectivity and causing more energy to be absorbed and less to be reflected back into space.
Then there is thermal pollution, we use nuclear plants as one means of making power, they’ve got those huge cooling towers dissipating waste heat. Typical thermal conversion efficiency is less than 40%, which means if you have a nuclear plant that is generating 800MW of electricity, it’s actually making 2 GW of thermal heat energy, of which 800MW is being turned into electricity and the remaining 1.2 GW is dissipated as heat. This is a non-trivial amount of heat, enough to heat a river used for cooling by several degrees. Collectively, all of these sources have some effect.
What can we do? The truth is that we can’t eliminate our warming of the planet entirely, we can only minimize it by the efficient production, use, and distribution of energy in the most environmentally friendly means possible.
We lose approximately 17 percent of the power we produce in transmission. If we converted all of the AC transmission lines that are 300km or longer to DC transmission, we’d be able to approximately double the transmission capacity, eliminate electromagnetic radiation from the power lines, reduce transmission losses to low single digits, eliminate cascading failures, eliminate sensitivity to space weather, and without changing the transmission lines or insulators, only changing the terminal equipment would give us these gains.
A new type of fusion reactor, known as a polywell or Bussard reactor after it’s inventor, may soon provide an alternative energy source that can generate electricity directly using a reverse magnetoplasmadynamics method of generation rather than a thermal cycle, and this may make efficiencies as high as 80% possible but we shouldn’t count our eggs before they’re hatched. While this technology is looking very promising, seven generations of reactors have been built and the last research reactor before a commercial power reactor, is currently being tested. But until it’s online producing power we can’t know that it will pan out so in the meantime we should continue to invest on renewable sources of energy such as thermal, solar, geothermal, etc, which add neither heat nor carbon dioxide to the environment.