Doug Hoffman: New Global Energy Balance Data Shows Climate Models Profoundly Uncertain

  • Date: 29/10/12
  • Doug Hoffman, The Resilient Earth

Earth’s climate is controlled by the global balance of energy. Radiation from the Sun heats up the planet while heat energy is re-radiated into space through complex interactions of land, sea and air. The journal Nature Geoscience has just published an update about the balance that controls Earth’s temperature and overall climate. Scientists conclude the global balance of energy flow within the atmosphere and at Earth’s surface cannot be accurately measured using current techniques and is therefore uncertain. The current uncertainty in this net surface energy balance is an order of magnitude larger than the changes associated with greenhouse gasses. In short, previous estimates of climate change are invalid, swamped by fundamental uncertainty.

Long-wave radiation received at Earth’s surface is significantly underestimated by earlier computer models. Precipitation estimates, related to surface radiation, are also out of whack. Those are statements made in “An update on Earth’s energy balance in light of the latest global observations.” In that paper, an ensemble of authors, led by Graeme L. Stephens of Cal Tech’s Jet Propulsion Laboratory, discuss the seminal importance of Earth’s energy balance to climate. Their conclusions to not bolster the case put forth by climate scientists and computer modelers in particular. Here is the article’s abstract.

Climate change is governed by changes to the global energy balance. At the top of the atmosphere, this balance is monitored globally by satellite sensors that provide measurements of energy flowing to and from Earth. By contrast, observations at the surface are limited mostly to land areas. As a result, the global balance of energy fluxes within the atmosphere or at Earth’s surface cannot be derived directly from measured fluxes, and is therefore uncertain. This lack of precise knowledge of surface energy fluxes profoundly affects our ability to understand how Earth’s climate responds to increasing concentrations of greenhouse gases. In light of compilations of up-to-date surface and satellite data, the surface energy balance needs to be revised. Specifically, the longwave radiation received at the surface is estimated to be significantly larger, by between 10 and 17 Wm−2, than earlier model-based estimates. Moreover, the latest satellite observations of global precipitation indicate that more precipitation is generated than previously thought. This additional precipitation is sustained by more energy leaving the surface by evaporation — that is, in the form of latent heat flux — and thereby offsets much of the increase in longwave flux to the surface.

Simply put, there is more energy coming into and leaving Earth than accounted for by climate models. The article is broken into a number of sections: The global annual mean energy balance; The energy balance and climate change; and The challenge ahead. The most interesting information is presented in the middle section. Citing improved measurements and measurement techniques, primarily through the use of satellites, the authors itemize the shortcomings of previous energy estimates.

“Although the earliest depictions of the global annual mean energy budget of Earth date to the beginning of the twentieth century,” Stephens et al. state, “the most significant advance to our understanding of this energy balance occurred after the space age in the 1960s.” Despite that leap forward, it has not been until the past few years that the influence of clouds on atmospheric and surface fluxes became known. These influences had to wait until satellite measurements of the vertical structure of clouds became available.

It has long been known that Earth’s climate is determined by the flows of energy into and out of the planet and to and from Earth’s surface. Geographical distribution of energy at the surface are particularly important and manifests itself in a number of physical phenomenon: it drives ocean and atmospheric circulation; it promotes the evaporation of water from Earth’s surface, which governs the planetary hydrological cycle. Changes in the surface energy balance, acting through variation in the hydrological cycle, dictate climate change. Global surface energy balance, the difference between top of atmosphere (TOA) and surface energy, is shown in the illustration below.

Observed and climate model predicted energy fluxes, given in Wm−2, both in and out of the TOA (a) and at the surface (b) are shown. The observed fluxes are from the paper’s supplemental information and the climate model fluxes are from simulations by the World Climate Research Programme’s Coupled Model Intercomparison Project phase 5 (CMIP5). The fluxes from a 16-model ensemble are summarized in terms of the range in model values (maximum and minimum fluxes) with the ensemble mean fluxes shown in parenthesis.

“SW in” and “SW out” are the incoming and outgoing short-wave solar fluxes at the TOA and “LW out’”is the outgoing long-wave radiation. Similarly “SW down” and “SW up” refer to downward and upward solar fluxes at the surface, and “LW up” and “LW down” refer to the upward emitted long-wave radiation from the surface and the downward long-wave radiation emitted from the atmosphere to the surface, respectively. SH and LH are sensible heat and latent heat fluxes. It is clear that the imbalances are very small compared with the total energy involved.

The bottom line on this analysis, effectively a recap of the state of climate science at the end of the first decade of the new millennium, is that our lack of certainty about the energies involved dwarf the supposed contributions to global warming by greenhouse gasses. Here is how Stephens et al. sum up the situation:

The net energy balance is the sum of individual fluxes. The current uncertainty in this net surface energy balance is large, and amounts to approximately 17 Wm−2. This uncertainty is an order of magnitude larger than the changes to the net surface fluxes associated with increasing greenhouse gases in the atmosphere.

In other words, the radiative forcing due to doubling CO2, estimated to be ~4Wm−2, is lost in the noise of uncertainty. The Earth system must balance in terms of energy in and energy out. Changes to that balance cause climate to change until a new equilibrium is achieved. This effectively reduces predicting climate change to balancing the “fluxes” in the system. “Because previous energy-balance studies have generally failed to address the uncertainties in these flux components, subsequent adjustments to surface fluxes to achieve balance have little merit,” the authors conclude.

Hurricane Sandy is just Earth’s environment working on its energy balance.

What this means is that all current climate models are based on bad assumptions. And because the raw output of those models do not reproduce the actual state of the environment, climate modelers have applied “adjustments” to get the numbers to work out. The result is that climate models are both fundamentally wrong and have been wrongly adjusted—no wonder they have not provided correct predictions of Earth’s future climate. This is just the latest revelation of flaws in climate science’s understanding of the system they are trying to predict. Worst of all, the magnitude of the error dwarfs the slight variation supposedly caused by greenhouse gas, totally invalidating predictions of future climate catastrophe.

It would be reasonable to assume the climate catastrophists would be embarrassed and would apologize for the ruckus they have caused over the past several decades, but no, that is not how it is. You see, scientists are wrong most of the time, it is the way the profession works. For every good theory there are thousands of others, from bad to bogus, that are tried and rejected. Scientists learn to shrug and move on to the next theory.

Unfortunately, the scientifically illiterate news media and agenda driven eco-alarmists seize on each new prediction of disaster as scientific “truth.” The only truth in science is that today’s theories are practically guarantied to be replaced by new theories tomorrow. Believe today’s global warming “truth” at your own peril, because even scientists will tell you it is erroneous.

Be safe, enjoy the interglacial and stay skeptical.

The Resilient Earth, 29 October 2012