What science knows about Anthropogenic Global Warming:
Though conspiracy theories are fostered on flagrantly false propaganda outlets, when we discus climate research we are discussing hard science. There are fundamental truths that guide the research, and these truths are irrefutable. They are not subject to debate, and there is no uncertainty.
Make no mistake, the system is complex, and there is significant underlying uncertainty within the models and projections. We can discuss what that means, and how we could and should react to the projections… But this is what we know:
- Energy can be bound in mass, bound in a molecular bond, or bound in a state of phase change. Otherwise,
- it can be transferred by contact (conduction), or it will gradually be released by means of electromagnetic radiation at a rate that can be determined by the “Stefan-Boltzmann Law”.
- The Earth and its atmosphere, as a single system, are isolated by the vacuum of space from all other objects, which means thermal radiation is the only means of releasing energy.
- The energy radiated from Earth/atmosphere system must equal the total sum of the solar radiation energy striking Earth (~99%), the total amount of energy released from nuclear fission occurring in the Earth’s core (~1%), and the total amount of energy released from industrial processes utilizing fossil fuels or nuclear energy by mankind (~0.01%), or the energy state of the planet must increase. This is due to the law of conservation of mass and energy (there is no known mechanism by which the additional energy would be bound up by the creation of mass).
- Certain compounds have chemical traits that make them capable of absorbing radiated energy of specific spectral range. When those compounds are struck by electromagnetic radiation that has the specific spectrum of interest, the molecules absorb the energy and begin moving faster (they become “hotter”), and immediately begin conducting the additional energy to whatever touches them, and radiating more energy until they again reach a temperature equilibrium with their environment (in which case all of the materials around them are conducting and radiating energy at the same pace, so they are absorbing and releasing energy at the same rate and have achieved an equilibrium energy state with respect to one another).
The five items listed above do not sound like what you generally hear from the infotainment industry – but THIS is the foundation of the Greenhouse Effect. It is neither partisan nor controversial; it is just a collection of unassailable facts about energy transfer that have been proven ad nauseum in controlled lab experiments dating back to the 1870’s.
Item #5 above is well understood intuitively by most 9th grade physical science students: I’ll give you an example: Pine needles on a healthy tree will absorb electromagnetic spectra of 300-500 nano-meters (nm) and will absorb spectra of ~525 – 750 nm… but will not absorb electromagnetic spectra of 500-525 nm; instead that light (our eyes since this as a deep “green”) is not absorbed, but is instead reflected. Another example: glass for efficient windows neither absorbs nor reflects most light in the visible spectrum range, but does absorb infrared spectrum, so light passes freely, but the infrared energy is absorbed by the glass panes and re-conducted back towards whichever side of the window was irradiated. This simply occurs, and is an inherent property of all materials. Each have certain spectra that they are quite efficient at absorbing and certain spectra that they are incapable of absorbing. The spectra that is not absorbed is either reflected (or refracted – but I’m trying to keep this simple) or passes right through, while the spectra that is absorbed then results in increasing the temperature of the material until the energy is conducted or radiated away.
H2O, CO2, CH4, N2O, CFC’s, and a few trace other compounds found in the Earth’s atmosphere, all have properties that involve the absorption of specific spectrum ranges of energy that fall in the broad category of “infrared”.
How well the materials absorb infrared radiation is important, because that is how the planet and atmosphere can release energy. The total amount of energy released per second from a radiator is partially dependent upon the material in question: cold rolled steel of a certain temperature might emit energy at more than 70 times the rate than a similar surface of polished silver that is the same temperature… but the distribution of the energy that is emitted is based on temperature. The Earth is a resonator that has a temperature of between 270 and 310 K, and the atmosphere is a resonator of around 255 K. As you can see, these temperatures result in curves that have essentially zero emissions of wavelengths smaller than 4 microns. The bandwitdths of absorption for H2O, CO2, and CH4 (the 3 most significant “greenhouse gasses” shown below clearly fall within the peak emission spectrum of the relevant temperature ranges.
This is Global warming. If the concentration of these gasses increase, then the likelihood that any given emitted radiation will strike a molecule of that gas, and some portion of the energy will be absorbed by the molecule – which will immediately begin moving faster and smashing into other molecules around it (conducting the energy into the broad atmosphere), and the atmosphere will re-radiate some of that energy – a portion of which will be redirected back towards Earth.
By the late 1800’s, the only issues that were left unsolved were:
- Whether the greenhouse gasses would increase in their concentrations or be balanced by natural forces (this has been fully resolved); and
- How the gradual buildup of additional energy would manifest in our vastly complex climate (until the average temperature increased enough to again achieve equilibrium due to the 4th power temperature dependence in the Stefan Boltzmann Law). THAT problem is complex to a degree that it has not been fully resolved, and may never be fully resolved to a 100% certainty.
A very simple example of what is unknown about HOW the additional energy would manifest… The temperature is not increasing nearly as quickly as early models projected, but the ice is melting far faster. We know that the Earth is warming, and must warm due to the additional buildup of GHG’s, but no-one can tell how much energy will be downwelled into the deep ocean vs absorbed by melting ice vs released by causing greater storm damage. The models all have their projections, and their uncertainties… and the most likely outcome will be some combination of all of the above (and more)… but though simple physics can explain that the Earth must and will warm, what that will mean over the next few decades and centuries is extremely complex, and multi-faceted. It’s a big planet, and there is a capacity for more than a single type of weather phenomenon at once. We could see record-shattering precipitation in New England while California suffers under its fourth year of continual extraordinary drought (for instance).
However, great strides have been made in seeking to understand it, and the projections are reported honestly – including the relative uncertainty of any given outcome based on current models, and the confidence of the models themselves, and the feedback mechanisms that were and were not considered within the models, etc…
So while the uncertainty exists – indeed the first root article connected to this explanation demonstrated that the median model in 2007 may have been off by more than 60% on the rate of arctic ice loss, that uncertainty is acknowledged openly and every effort is being made to reduce those uncertainties.
The knowledge base has been doubling every 2-3 years in this field, and the people who work on it are drawn by the challenge of one of the most complex problem mankind has ever faced. They may be imperfect, and the findings are not always consistent nor are they always correct, but the underlying science is irrefutable, and those working in this field deserve respect.
If you are listening to a propaganda outlet that expresses otherwise, I would strongly advise that you eliminate them from your sources of information, because they are only serving to misinform you and make you sound extremely foolish. If you hear someone express some cockamamie notion that “the science isn’t real, it’s all some vast conspiracy”, then I’m afraid that this is the only valid response.
If you have honest, non-trollish questions or comments, I would be happy to answer them as best I can. Just drop a note in one of the articles that links to this explanation.
Please also read our more in depth article about the Arctic Ice Extant.