Guest Post: Parliamentary Commissioner’s Report Wrong about Livestock Methane

A guest post by Professor Emeritus Geoff Duffy:

The recent statement from the Parliamentary Commissioner for the Environment, Right Hon Simon Upton, regarding methane emissions from livestock, conflicts with experimental data.

Computer climate models are accurate only if all significant variables are incorporated simultaneously. Leave one out or miscalculate its effects and the model predictions will be inaccurate—no better than a guess and inadequate for policy.

The major elements of the global weather system are fairly well identified, but the magnitudes of many effects are poorly understood. For example, the IPCC doesn’t know whether increased cloud cover, predicted to be caused by warming, would result in further warming or cooling. Global cloud cover has been studied for many years, but their latest report (AR5, 2013), admits they don’t know whether it is expanding or shrinking, which means they can’t say what warming—if any—our emissions might cause.

The factors involved in the weather are numerous and their interactions chaotic. Nearly three-quarters of the surface of our planet is covered in oceans and lakes, and two-thirds of land and sea at any moment is covered in clouds. Just over half the sun’s energy actually reaches the earth’s surface, with its re-radiation back from land and water very important in heating the atmosphere, and there are many more mechanisms in play. The massive mixing effects of winds, storms and rain, ocean waves and currents and the creation and dissipation of clouds must be included in climate models. If they are not, predictions will be erroneous.

Evaporation at sea level and condensation of water vapour into clouds are important. Clouds can precipitate rain or snow, further cooling the atmosphere, land and ocean. Gaps in these areas of knowledge caused all 102 CMIP-5 climate models relied on by the IPCC to fail to predict recent global temperatures, which have been essentially constant for two decades, despite carbon dioxide rising 9% in that time.

Conduction is another energy transfer mechanism between atmospheric molecules, water and land. Radiant energy absorbed by greenhouse gases (GHG) increases their speed (they get warmer), so when they collide with other molecules, even non-GHGs (nitrogen, oxygen, argon), they transfer heat to them and the atmosphere warms.

Two factors stand out in the calculation of atmospheric energy transfer: a GHG’s level in the air and how much electromagnetic energy it absorbs at different frequencies.

The electromagnetic energy spectrum has been studied for over 200 years. Atmospheric physicists have long known that the most plentiful and effective greenhouse gas is water vapour (WV), which absorbs energy over 80% of the entire energy spectrum, whereas carbon dioxide absorbs over less than 10% of the spectrum. Methane is even weaker, absorbing under 1% of the spectrum.

So the Commissioner is incorrect when he says: “The three main greenhouse gases are carbon dioxide, methane and nitrous oxide.” Neither carbon dioxide, at 406 ppm, nor methane, at 1.8 ppm, can dominate, because their concentrations are insignificant. At 10,000 ppm, water vapour overwhelms them both. Comparing methane with WV is like putting a mouse up against an elephant. WV is 25 times more abundant than carbon dioxide and 5,000 times more abundant than methane.

Examining methane alone doesn’t reveal what’s happening in the atmosphere. The following statements from the Commissioner’s Report are quoted and in bold; my comments follow.

“[methane] is a more potent greenhouse gas than carbon dioxide”– p. 8 This is only true when the gases are at the same concentration, but they’re not. Carbon dioxide is always and everywhere 220 times more plentiful and accesses a wider range of the energy spectrum. It is also much more potent than methane.

“methane traps … heat”– p. 8 Absolutely no heat is ‘trapped’. A GHG molecule absorbs electromagnetic energy, which energises it to move faster until it collides with another molecule (oxygen, nitrogen, argon, carbon dioxide and all), and gives up some energy in making the other molecule move faster. The authors of the report do not understand heat transfer, as the ‘trapping’ concept was debunked years ago. There is no ‘blanket’, there is no greenhouse. If the modelling does not include all the effects other than radiation the predictions will be wrong.

“A constant flow of methane emissions results in a constant methane concentration after 50 years, but its impact on temperature continues to increase for several centuries.” – p. 8 The claim that methane continues to increase temperatures over centuries is wrong, because we don’t observe it—there has been virtually no temperature change for 20 years or more, even as methane rose by 5% and carbon dioxide by 9%, and we do not have centuries of methane data.

“However, the warming effect of that methane would continue to increase, at a gradually declining rate, for more than a century. In the year 2050, holding New Zealand’s livestock methane steady at 2016 levels would cause additional warming of 10-20 per cent above current levels”. – p. 11 With carbon dioxide concentration 220 times greater than methane and rising for two decades without much increasing the temperature, it is wrong to reason that methane—the weaker, less numerous species—has more influence.

We should not use rudimentary mathematical models for simulation or prediction, without strong and consistent experimental data to support the claimed effects. Such models will produce inaccurate predictions unless they include all the energy mechanisms (radiation, convection, conduction, molecular collision) and mass transfer effects (evaporation, condensation, precipitation, phase-change, storms, etc.) involved in the climate system.

At crucial points this report mischaracterises the science and lacks proper scientific understanding. It should be withdrawn until verified by independent scrutiny.

Dr Geoff Duffy FRSNZ, DEng, PhD, BSc, ASTC Dip., FRSNZ, FIChemE, CEng is Professor Emeritus – Chemical Engineering, University of Auckland