Primer on Global Warming and Climate Change – Part III (Mitigation and Adaptation)

Faced with the imminent dangers of climate change and global warming, we have three options:

  1. Mitigation, meaning measures to reduce the pace & magnitude of the changes in global climate being caused by human activities.
  2. Adaptation, meaning measures to reduce the adverse impacts on human well-being resulting from the changes in climate that do occur.
  3. Suffering the adverse impacts that are not avoided by either mitigation or adaptation.

Human-caused climate change is already occurring (see Part II) and adaptation efforts are already taking place. Some of the adaptation efforts have been to change cropping patterns, and develop heat-, drought-, and salt-resistant crop varieties. Strengthening public-health & environmental-engineering defenses against tropical diseases is also in the works. Other efforts include building new water projects for flood control & drought management; building dikes and storm-surge barriers against sea-level rise and avoiding further development on flood plains & near sea level. However, adaptation becomes costlier and less effective as the magnitude of climate changes grows. Besides, the poorer nations may not have the technological and other resources or political will for adaptation and be most affected from global warming even though they are not the biggest polluters. The greater the amount of mitigation that can be achieved at affordable cost, the smaller the burdens placed on adaptation and smaller the suffering. Thus mitigation and adaptation are both essential in our battle against global warming and climate change.

The remainder of this primer focuses mainly on mitigation – the size of the need, the available approaches, and the policy levers and prospects. Most of the material presented is from the IPCC 3rd & 4th Assessment reports; the OECD Climate Change and Development report and from the various lectures, presentations and papers by Dr. Holdren who is a noted global expert on climate change policy.

Green House Gases – The size and sources of Emissions

Since pre-industrial times, increasing emissions of GHGs due to human activities have led to a marked increase in atmospheric concentrations of the long-lived GHG gases carbon dioxide (CO2), CH4, and nitrous oxide (N2O), perfluorocarbons PFCs, hydrofluorocarbons (HFCs) and sulphur hexafluoride (SF6) and ozone-depleting substances (ODS; chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), halons) and the human-induced radiative forcing of the Earth’s climate is largely due to the increases in these concentrations. The predominant sources of the increase in GHGs are from the combustion of fossil fuels. Figure 1 depicts the global anthropogenic greenhouse gas emissions in 2004 and Figure 2 provides the sources of GHG emission in 2004 by sector.

Figure 1. Global GHG emissions, IPCC WG3, 2007

Figure 2. The sources of GHG emissions, IPCC WG3, 2007

What’s a suitable target for CO2 reductions?

The climate-policy aim negotiated in the process of formulating the UN Framework Convention on Climate Change was: “stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system”.

There was no formal consensus at that time about what level is “dangerous” in this sense. But it’s becoming increasingly clear that the current level of anthropogenic interference is dangerous. Significant impacts in terms of floods, droughts, wildfires, melting ice are already evident at ~0.8°C above pre-industrial values.

The assumptions about GHG concentration levels for stabilization of atmospheric concentrations range from 450, 550 and even 1000 ppmv. According to the IPCC third assessment report, increase of CO2 concentrations in this range can lead to an equilibrium warming of between 2.0 °C to 4.8 °C. However, it is now entirely plausible that an increase in average temperature (∆Tavg ) of 1.5 °C will mean the end of coral reefs & polar bears; ∆Tavg ~ 2°C will mean catastrophic melting of Greenland & Antarctic ice and lead to multi-meter rises in sea level; and ∆Tavg ~ 2.5°C will sharply reduce global crop yields.

Thus stopping at 2x pre-industrial CO2 (550 ppmv, corresponding to ~3°C), may not be good enough. Many analysts & groups now conclude that prudence requires aiming not to exceed 2°C. However, stabilizing at 450-500 ppmv would be possible only if emissions were flat for ~50 years, then declined. The stabilization of GHG concentrations and, in particular, of the main greenhouse gas, CO2, requires substantial emission reductions, well beyond those built into existing agreements such as the Kyoto Protocol.

Mitigation by sustainable forest, soil and land management practices

This approach involves increasing carbon sequestration and conservation. Vegetation can bind carbon and remove it from the atmosphere, which helps to mitigate climate change. There are several ways of increasing the sequestration and conservation of carbon, for example through carbon sinks, by improving vegetation management, etc. Techniques involve reforestation, afforestation, avoided deforestation and improved management of agricultural soils. Accelerating reforestation and afforestation of degraded land can increase sequestration and help mitigate GHG emissions as can reduction of emissions of CO2 from deforestation in the tropics.

Improving management of agricultural soils to increase carbon storage can have a huge impact on mitigation. Practices such as conservation tillage not only reduce the energy needed to maintain land but also increase the soil’s capacity to bind and sequester carbon, and generally improve soil quality by allowing organic residues to decompose naturally. Reducing the use of fertilizers also emissions from their production and application. The quality and long-term viability of soil can be improved by improving the nutrient balance through the timing of fertilizer applications, the use of nitrification inhibitors and the utilization of existing nitrogen from organic matter instead of from fertilizers.

IPCC 3rd Assessment optimistically estimated a total potential of 100 billion tonnes C uptake by 2050 (~20% of emissions) from this approach.

Mitigation by reducing emissions of methane (CH4) and soot

Though CO2 is the main culprit, CH4 and soot also have been implicated in climate forcing contributing as much as 20% to the overall forcing. It has a global warming potential greater than that of CO2 in the next 100 years.

Anthropogenic methane (CH4) comes 30% from energy systems, 30% from livestock, 25% from agriculture, 15% from landfills & waste treatment. The good news is that technical means exist for reducing all of these and given methane’s relatively short atmospheric lifetime means emissions reductions translate quickly into reduced concentrations, thus reduced forcing. To decrease emissions from natural decay of wastewater, crop and animal wastes, waste can be collected and stored in anaerobic digesters that range in size from large industrial ponds to small tanks suitable for single households. To reduce emissions from ruminant animals (such as cattle, buffaloes, goats, sheep, etc that produce higher emissions due to higher feed intake) alternative livestock farming practices can be employed, such as ruminant enteric methane management.

Soot comes from 2-stroke & diesel engines as well as from traditional uses of biomass fuels, agricultural burning, and forest fires. The engine and biomass fuels emissions are amenable to sharp reduction by technical means. Again, the very short atmospheric lifetime of soot (days to weeks) means emissions reductions translate quickly into reduced forcing.

Mitigation by Geo-engineering

Geo-engineering is “the intentional large scale manipulation of the global environment” to counteract the effects of global warming. Some geo-engineering feats proposed to cool the earth include building carbon-scrubbing towers that would capture CO2 from the atmosphere, shooting droplets of seawater into clouds to enhance their reflectivity and ocean fertilization to increase carbon uptake by phyto-plankton. However, many scientists worry that attempts to fool mother nature will create bigger problems than those they aim to solve. Reflectivity of man-made surfaces (buildings, roads) can be increased, but global impact is limited by small fraction of land surface used for these purposes (~2%). Large-scale alteration of reflectivity of oceans would be expected to have undesired climatological & ecological side effects. And efforts to increase the atmosphere’s reflectivity by injecting reflecting particles into the stratosphere might be affordable (& reversible), but would be likely to deplete stratospheric ozone. “Scrubbing” CO2 out of the atmosphere technologically appears to be 5-10 times more costly than capturing it before emission at power plants and ocean fertilization to increase carbon uptake by phyto-plankton currently looks questionable both in terms of efficacy and in terms of undesired side effects..

Mitigation by reducing CO2 emissions from energy systems

CO2 accounted for 45% of the total positive anthropogenic forcing from 1750 as of 2000 according to IPCC 4th assessment report. Under the BAU (business as usual) scenarios, it would account for 60% in 2100. Fossil-fuel combustion is the dominant source of anthropogenic CO2 emissions. Anthropogenic CO2 emissions in 2005 were ~7.5 GtC from fossil fuels, 0.2 GtC from cement production, 1.5-2.5 GtC from deforestation & fires.

Let’s look at the factors driving carbon emissions. The emissions arise from a 4-fold product:

C = N x Y / N x E / Y x C / E

where C = carbon content of emitted CO2 (kilograms), and the four contributing factors are:
N = population, persons
Y / N = GDP per capita, $/pers
E / Y = energy intensity of GDP, GJ/$
C / E = carbon intensity of energy systems, kg/GJ

Consider the data given below for the years 2000, 2050 and 2100:


  2000 2050 2100
Population, billions 6.1 9 10
Economy, trillion 2000$ 45 150 480
Energy, exajoules 450 900 1800
Fossil C in CO2, gigatons 6.4 14 21

(These numbers correspond to 2.4%/yr avg growth of real GDP, 1.0%/yr decline in energy intensity of GDP, and 0.2%/yr decline in C intensity of energy supply).

Based on these numbers, in the year 2000, the world emission of Carbon was:
6.1×109 pers x $7400/pers x 0.01 GJ/$ x 14 kgC/GJ = 6.4×1012 kgC = 6.4 GtC.

So, obviously reductions in the contributing factors will lead to stabilization. However, it is clear that in the near future, population decrease or per capita GDP decrease are not plausible alternatives, especially for developing countries. But if this GDP growth comes at the expense of environmental degradation then perhaps we are in long run not getting richer. In a recent world study it has been shown that beyond a certain level of development, happiness is not linked to GDP. Hence some lifestyle changes in the industrialized nations could, in fact, increase the quality of life even though they reduced GDP. And, reduction in population growth can only be achieved through social incentives like providing education, health care, and opportunity for all.

Thus, carbon intensity of the energy system and energy intensity of GDP have to be also reduced to compensate for an increase in carbon due to an increase in GDP and population so as to reduce total emissions. Let’s look at these two contributing factors.

Energy intensity of GDP. Improved energy efficiency, i.e., getting more GDP out of less energy offers the largest, cheapest and fastest leverage on carbon emissions. Applying energy efficiency measures improves the use of natural resources and fossil fuels, thus reducing emissions and easing the pressure on our resources. It entails more efficient cars, trucks, planes, buildings, appliances, manufacturing processes.

Oil used as transport fuel contributes to 25% of global CO2 from fossil-fuel combustion. Growth in these uses can be reduced by increasing the efficiency of cars, trucks, buses, trains, aircraft, etc; increasing the load factors of these (e.g., passengers per vehicle per trip); by mode switching (e.g., taking public transport instead of driving, using trains for industrial transport instead of trucks); by urban & economic planning that affects living & production patterns so as to reduce commuting and freight transport, etc.

Heating, cooling , refrigeration, lighting, office equipment contribute to 33% of global CO2 from fossil-fuel combustion. Energy used for these purposes can be reduced by improvements in building envelopes (wall & roof insulation, high-performance windows); improved building orientation, shading, passive energy storage; increased efficiency of heating & cooling (improved furnaces, air conditioners, ground-water heat pumps); increased efficiency of lighting, refrigerators, computers, other appliances, etc.

Industrial energy use contributes to 40% of global CO2 from fossil-fuel combustion. Biggest users include oil refining, plastics, fertilizers, iron & steel, aluminum, cement, pulp & paper. Energy used for these purposes can be reduced by improved efficiency of electric motors & individual industrial processes; increased use of on-site combined heat & power (CHP); increased recycling of energy-intensive materials; shift in composition of industrial activity from materials-intensive to knowledge- and information-intensive goods & services, etc.

Carbon intensity of energy supply. This ratio too has been falling, but more slowly than energy intensity of GDP. Reducing it entails changing the mix of fossil & non-fossil energy sources (most importantly more renewables and/or nuclear) and/or the characteristics of fossil-fuel technologies (most importantly with carbon capture & sequestration). A possibility for reducing the carbon intensity is increasing the efficiency of conversion of fossil-fuels to end-use energy forms (most importantly electricity). The potential here is limited because conversion efficiencies are constrained by thermodynamics and already high. Switching from high C/E to low C/E fossil fuels (coal to oil & natural gas, oil to natural gas) is another possibility. Again the potential is limited because oil & gas are much less abundant than coal (unless unconventional gas resources become practical). Some other possibilites are CO2 capture & sequestration (CCS) when fossil-fuels are converted or burned and switching from fossil to non-fossil primary energy sources (renewables & geothermal, nuclear, etc.).

Policy options embraced to date

In 1988, the Intergovernmental Panel on Climate Change (IPCC) was created by the United Nations Environment Programme (UNEP) and the World Meteorological Organization (WMO) to assess the scientific knowledge on global warming. Its first major report in 1990 showed that there was broad international consensus that climate change was human-induced. That report led way to an international convention for climate change. This became the United Nations Framework Convention on Climate Change (UNFCCC), signed by over 150 countries at the Rio Earth Summit in 1992. (By the end of 2006, over 180 countries had signed and ratified it).

The Convention took effect in 1994. By 1995 negotiations had started on a protocol – an international agreement linked to the existing treaty, but standing on its own. This led to the Kyoto Protocol, adopted unanimously in 1997. The main purposes of this protocol was to 1) Provide mandatory targets on greenhouse-gas emissions for the world’s leading economies all of whom accepted it at the time; 2) Provide flexibility in how countries meet their targets; and 3) Further recognize that commitments under the Protocol would vary from country to country.

As a general principle, it was also recognized that most of the greenhouse gas emissions contributing to climate change come from the industrialized countries, that have been developing since the Industrial Revolution, as such emissions remain in the atmosphere a long time. In addition, they have been developing for longer than the developing and third world nations, so action to address this must proportionately be with those industrialized nations. The Kyoto Protocol hailed as a landmark in negotiated global commitment to move forward to address the problem has sadly fallen short as it is limited in time frame, magnitude of required reductions, and global participation (particularly from some of the world’s biggest polluters).

At the 14th Conference (COP 14 or the Poznan Climate Conference) last December, several important issues were covered. This conference continued from where the previous COP 13, the Bali Conference, left off; to discuss a post-Kyoto international agreement on climate change to take effect in 2013. The key outcomes are: 1) management of a UN Adaptation Fund to help developing countries (who will worst hit by the effects of climate change) agreed; 2) funds can now be disbursed using a 2% levy on carbon trading under the UN Clean Development Mechanism; 3) progress on how environment-friendly technology can be transferred to developing countries; 4) agreement that deforestation needs to be reduced; and 5) recognition that the situation is quite urgent.

This conference will be followed up by a Copenhagen conference this year (December, 2009) to finalize the agreement for 2013.

India’s position and policies on climate change

India and other developing countries feel strongly that they are not responsible for the threat of climate change that has been created. Unsustainable consumption patterns of the rich industrialized nations in the world are responsible for it. While the richest countries have produced the bulk of the pollution blamed for climate change, developing countries are producing increasing volumes of gases. But developing countries say their climb out of poverty should not be halted to fix damage done by industrial countries. Yet, India and other developing country economies may be highly vulnerable to climate change. India’s food production would be adversely affected. Sea level rise would displace a large number of people. The developing countries are particularly vulnerable to the likely increase in the incidence of extreme events.

The impacts of climate change could hinder development and delay progress in eradicating poverty, potentially aggravating social and environmental conditions. Though India is the world’s 5th largest emitter (US, Europe, China and Russia being the top four), India’s per capita emission of carbon is one fourth of the global average. Even the top 10% of urban population emits well below the global average per capita emission. Yet, it is in the interest of India, and other developing countries, in making significant progress in limiting GHG emissions through policies that aim to improve energy and economic efficiency of the energy and industrial production capacity, as well as energy development, both conventional and renewable, which target improved environmental quality and limit human health hazards from air pollution.

India has for quite some time pursued GHG friendly policies in it’s own interest. India’s obligation to minimize energy consumption – particularly oil consumption – and to deal with its environmental problems prompt it to follow many such policies. Directly or indirectly these efforts are made by Government as well as by people to reduce energy consumption. Some of these efforts are on-going for several decades and are institutionalised in a number of ways through policies, programmes and the creation of specific institutions. In addition, there are a number of measures taken by people themselves. Some because of resource-minimising cultural traditions as well as good practices that exist in India and some due to sheer poverty and deprivation. Indians have recently won the top spot on the world green index due to their environmentally sustainable behavior.

Concluding Remarks

Climate change is imminent and the effect of global warming a serious consequence and hence of urgent importance to take action. Reduction of GHG emissions is not a choice anymore but a necessity for the world’s survival. Mitigation and adaptation are both essential in our battle against global warming and climate change.

Some of the policy recommendations brought to the table by the climate change conferences have been to pursue a new global framework for mitigation and adaptation in the post-Kyoto period. Most agree that it must include mandatory, economy-wide reductions in GHG emissions below BAU everywhere, and it needs to be equitable, achievable, and adequate to the magnitude of the challenge. Technical and policy measures need to be vigorously pursued that address economic, social, and non-climate environmental goals as well as climate. Increasing investments in energy-technology innovation is warranted worldwide along with increased incentives for innovation in the private sector. Expanded international cooperation on energy-technology innovation is needed to reduce costs & spread benefits in implementing climate-friendly technologies in the interest of the whole world.

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