The Science of Climate Change.

To achieve an optimum benefit for Nigeria, not only is it imperative that policy makers fully understand the social, economic, environmental, financial, technological and political issues around the subject, but the generality of Nigerians need to be widely aware of changes in the global village they live in especially in the way energy is to be viewed in the wider world around going forward. As the subject of Climate Change is somewhat technical, it may suffice to give a background on the subject before driving us through to the point we have reached so far. This is what these series of articles on the subject will try to achieve.

Early contributors to climate change include Fourier, Langley and Arrhenius. That the climate is changing is not contestable but what is being argued over the years borders on the main causes of climate change. Climate change is made possible by the increase in the atmospheric concentration of Green House Gases (GHG) such as Carbon IV Oxide (CO2), Nitrous Oxide (NO2), Methane (CH4), Hydrofluorocarbon (HFC), Perfluorocarbon (PFC), and Sulfurhexafluoride (SF6). All these gases absorb terrestrial infrared radiations.

The Green House (GH) effect is uncontested as without it, the earth would have been 33 degrees cooler. We average 15 degrees now but would have been -18 degrees. Infrared radiation from the high temperature sun has short wavelength. This is absorbed by the earth and some are reflected by both the earth and the atmosphere. The proportion absorbed by the earth warms up the earth to the suitable temperature required for the earth. With increasing concentration of GHG in the atmosphere, infra red radiations reflected into the atmosphere are absorbed and re-emitted to the earth. This tends to increase the average temperature on the earth surface once the concentration increases without any control. The balance between the incoming and outgoing radiation has always fluctuated from time immemorial in terms of the atmospheric constituents, their relative composition and concentration, solar variations etc and so has the corresponding changes in the climate. What has remained an argument is the degree to which the actions of mankind have contributed to this imbalance.

This is the so called Anthropogenic Climate change which is Contestable. The disagreement exists on the degree to which human induced changes in the atmospheric make-up have altered the balance of the incoming and outgoing radiations. To begin with, water vapour which is about 1% of the atmosphere is responsible for 60 to 70 % of GH effect while all the other gases in the atmosphere, collectively making up approximately 0.04% of the atmosphere, are responsible for the rest 30 to 40% of Green House Effect. In terms of the radiative forcing, the Halocarbons are the most feared among GHG, followed by Nitrous Oxides and Methane before the least effect can be attributed to Carbon 1V Oxide. The global warming potential (GWP) is normally used to categorize the warming effect of GHG indexed to a molecule of CO2 integrated over 100 years. CO2 has a GWP of 1, Methane-21, NO2–310, Perfluorocarbons-9,200, Hydrofluorocarbons-11,700, Sulphur hexafluoride–23, 900.

Emissions from GHG are quantified as carbon equivalents in one of two ways viz CO2 emission and Carbon emission. 1 tonne carbon is 3.7 tonne of CO2 (relative to molecular weight). If you consider the global flow of carbon today to be circa 200GTp.a, and that human-emission of carbon is 7.5GTp.a (this includes human carbon added to the atmosphere of about 3.4GTp.a), as a result, there has been a 32% increase in atmospheric carbon concentration since 1800. Infact, the changes in the concentration of the main GHG in the atmosphere from pre-industrial level to early 2001 reveal that NO2 increased from 275ppbV to 316ppbV (increase of 15%), CO2 increased from 280ppmV to 370ppmV (increase of 32%), and CH4 from 700ppbV to 1786ppbV (155% increase). These statistics are no doubt alarming!

The measurements no doubt, show the atmospheric concentration of GHG is increasing which may imply that global and regional temperatures are rising. Added to this, similar measurements have proved that sea levels are rising in consistency with the predictions made by earlier climate scientists. However, like every scientific hypothesis or conclusions, these measurements have degrees of accuracies or put in another way, uncertainties. For example, the uncertainties in the scientific analysis respecting temperature rises is that as the temperature rises, the degree of radiative forcing is modified by climate feedbacks, some positive (making it warmer) and others negative (making it cooler). Also, there are uncertainties associated with these feedbacks (water vapour, cloud, ocean circulation, ice snow albedo, land-surface/atmosphere interactions etc) which have given rise to a range of associated numbers in climate change with respect to temperature rises. One Inter Governmental Panel on Climate Change (IPCC) report estimates an increase in global average surface temperature of 1.4 to 5.8 degrees by 2100.

About 90% of human emission comes from fossil fuel via transportation, heating, and electricity. The remaining 10% comes from Agriculture, traffic pollution and industrial processes. So, almost all human emission or pollution is from energy. To understand the contribution therefore of the biggest emitters or polluters in the world, the global average mean of 1 tonne carbon/person/year is a good yardstick for comparison. The USA had a figure of 7 tonne carbon/person/year, the entire European Union (EU) had 3, China had 0.3 and Nigeria had 0.1 as at 2001. This shows that 80% of all emissions are from 20% of the global population. What a paradox! The high carbon emitters are geographically and financially able to cope but the low carbon emitters suffer geographically and are financially unable to cope with the effects of climate change.

To make it worse for the low emitters, they have less political influence in the global sense. Data from 1900 to 2004 shows that USA emitted 315GT of CO2, China- 89GT of CO2, Germany- 74GT of CO2, UK- 55GT of CO2, India- 25GT of CO2, Brazil- 9GT of CO2 and Indonesia- 6GT of CO2. (1GT equals 1012 Tonnes). Scanning through the CO2 that countries put into the atmosphere over the past century might seem irrelevant to modern climate debates but when we consider historical emissions like per capita emissions, it is a bone of contention at any talks regarding climate change because developing nations will argue that any cuts should incorporate the principle of historical responsibility which in short means the rich and developed countries should pay in the near future for their considerable past contributions to global warming.

What needs to be done to derive the most benefits from the just concluded Climate talks lie with those who understand energy. The developed nations will put such people in charge but in her characteristic manner, African leaders might allow nepotism, parochialism, anachronism, egotism, self-aggrandisement, and quota system to rob them off their only remaining benefit in this millennium. To this end, it is advisable that the Nigerian government should start to take a critical look at this issue and constitute a professional panel of local scientist to study, partner with their foreign counterparts so as to be able to adequately respond to challenges as it might arrive and affect the country as well as the continent as far as climate is concerned.