What may happen if we continue to emit greenhouse gases (GHG)? People talk of the 3 R's - Reduce, Reuse, Recycle. But is that enough?
It is likely that with elevated levels of GHGs (e.g. carbon dioxide, methane, nitrous oxide and CFCs) the average global temperatures would rise. The Intergovernmental Panel on Climate Change (IPCC) suggest that if GHG emissions continues to increase, by 2100 temperatures could rise by between 2.6 and 4.8°C (mean of 3.7°C) from preindustrial levels. This corresponds to sea levels rising between 45cm and 82cm (mean of 63cm) which could have devastating effects on coastal communities and ecosystems.
Figure 1. Coastal flooding in the Netherlands
The rise in temperature could dramatically alter weather systems resulting in more extreme events such as high rainfall and typhoons putting greater pressure on water and food resources. Ecosystems could be irreparably damaged.
Human societies now face a choice on whether to:
GHG emission can be lowered through a variety of strategies including:
The average period of time a substance spends in a place or condition (e.g adsorbed or dissolved) is referred to as the residence time. Some GHGs have long residence times in the atmosphere. Carbon dioxide can remain in the atmosphere for hundreds of years before being absorbed by the oceans or plants. However, planting more trees which absorb carbon dioxide could slow the rate of carbon dioxide increase within the atmosphere. If emissions levels were also dramatically cut, planting trees could lead to an overall reduction of atmospheric carbon dioxide levels.
Figure 2. Plants absorb carbon dioxide and stores the carbon in their biomass. Oxygen gas is released as a by-product.
As discussed in the previous subtopic, the impacts of climate change are already being felt across the globe. When dealing with these impacts we can be proactive and take action to minimize effects prior to them occurring and also reactive, take action once the impacts have occurred. For instance we can try and minimize the impacts of heavy rainfall by improving drainage (proactive) and if under extreme conditions flooding occurs, move people to a temporary safe location with adequate supply of food and water (reactive).
Due to the scale and global nature of climate change, international collaboration is necessary to tackle problems of rising GHG levels. Sharing of knowledge and expertise is vital to effectively cut emission levels and to deal with the on-going impacts.
Definition
The Intergovernmental Panel on Climate Change (2014) defines mitigation as: ‘A human intervention to reduce the sources or enhance the sinks of greenhouse gases (GHGs)'.
There are a variety of ways in which GHG emissions could be reduced:
Carbon dioxide can also be removed from the atmosphere by a range of methods referred to as geo-engineering, discussed in the next section.
Reducing energy consumption and therefore the amount of fossil fuel used can reduce emissions of greenhouse gases and other pollutants. Making energy efficiencies and employing energy conservation measures was discussed in subtopic 6.3 Photochemical smog.
Figure 1. Reducing the temperature on thermostat heating system and wearing an additional layer of clothes instead can save on energy costs as well as reduce energy use.
This involves replacing the use of fossil fuels with alternative such as nuclear, solar, wind, geothermal and hydropower. The advantages and disadvantages of using nuclear and renewable energy to generate electricity are discussed in subtopic 7.1 Energy choices and security.
Good transport is considered important for economic development e.g. effective movement of the workforce and goods. Road transport is considered to be major source of carbon dioxide and nitrous oxide. Methods to reduce vehicle emissions were discussed in subtopic 6.3 Photochemical smog, and include replacing petrol or diesel vehicles with electric powered or hybrid vehicles.
Alternatively some countries are opting to substitute fossil fuels with biofuels such as biodiesel and bioethanol:
Figure 2. Brazilian production of light vehicles by type of fuel - neat ethanol (alcohol), flexible fuel and gasoline (petrol) vehicles from 1979 to 2014.
However, there are a number of issues with growing biofuels:
Best management practices can be used to reduce GHG emissions from farming e.g.:
Figure 3. Rice cultivation in waterlogged conditions favours bacteria to produce methane.
Geo-engineering involves manipulating the earth’s environmental systems to counteract the impacts of climate change.
Geo-engineering methods do not address the causes of climate change but could be used to compliment GHG emission reduction strategies. Most have not been tested and little is known about their effectiveness, cost and environmental impacts. Two key approaches are:
Various methods are used to remove carbon dioxide ranging from biological absorption to chemical abstraction. These methods are unproven and carbon dioxide removal is likely to be a very slow process taking decades to stabilise atmospheric levels. Examples discussed below include land use management, use of biomass, carbon capture and storage and absorption by the oceans.
Land management can be used to protect and enhance plants that absorb carbon dioxide thereby reducing atmospheric levels. Carbon sinks can be protected and enhanced by:
Figure 1. Ploughing encourages loss of carbon from the soil.
In 2008 the United Nations set up a collaborative programme to reduce emissions from deforestation and forest degradation referred to as UN-REDD. The project recognises:
The UN-REDD supports developing countries to:
Watch the following video ‘REDD as part of the solution’ by UN-REDD and consider the benefits of REDD programmes:
When plant organisms die, the biomass degrades releasing carbon dioxide. An alternative is to harvest and use the biomass to generate fuel (replace use of fossil fuel) or to bury the material.
Figure 2. Rapeseed plants used to produce biofuels.
This method involves the removal of carbon dioxide from the atmosphere followed by either:
Air could be filtered through adsorbent material that removes the carbon dioxide from the atmosphere. Storage could be in underground sites e.g. geological formations previously containing oil or gas reservoirs.
CCS methods are currently under investigation and are likely to be very expensive.
Carbon dioxide is absorbed by photosynthetic phytoplankton in the oceans. The carbon moves through the food web and when organisms die they sink to the lower layers. From here the carbon can enter storage within the sediments. This absorption of carbon dioxide from the atmosphere and its movement into the deep oceans is referred to as the biological pump. The biological pump could be further enhanced by:
The consequences of using either method are unknown.
These methods are currently only theoretical. They focus on increasing reflection of sunlight back into space and therefore reducing the amount of solar radiation absorbed by the earth. For example:
Figure 3. Artist impression of potential reflectors in space used to deflect solar radiation from the sun.
Watch the following video ‘Climate change 2014: Mitigation of Climate Change’ by the IPCC and consider the following questions:
International-mindedness
Climate change is a global issue and therefore needs international effort to limit its impacts.
Definition
The Intergovernmental Panel on Climate Change (IPCC) defines adaptation as: ‘The process of adjustment to actual or expected climate and its effects. In human systems, adaptation seeks to moderate or avoid harm or exploit beneficial opportunities. In some natural systems, human intervention may facilitate adjustment to expected climate and it effects’.
Whereas mitigation addresses the causes of climate change by reducing emissions of greenhouse gases (GHG), adaption is focused on dealing with the effects. The long residence period of GHG in the atmosphere means that even if GHG emissions were dramatically cut, past emissions will continue to influence climate. Hence adaptation strategies are necessary to minimize negative effects and take advantage of any new favourable conditions.
Other differences between mitigation and adaptation include:
Through effective adaptation action we can develop the resilience (ability to cope) of our infrastructure (e.g. water, energy and transport) and built environment to climate change. Regulation can be used to implement adaptation and to have plans in place called contingency plans to deal with extreme events or disasters. Early warning systems e.g. forecast of extreme events (e.g. cyclone) can give local people time to prepare and e.g. evacuate the area or find suitable emergency shelter.
Figure 1. Adaptation involves making plans for the future to deal with climate change over the long term, short term and under emergency situations.
Examiner Tip
Ensure you are able to distinguish between mitigation and adaptation in addressing climate change.
Adaptation measures can be categorised by the sector they apply to. The sectors covered here include water resources, agriculture and fisheries, ecosystems, coastal systems and low lying areas and human health.
Changing precipitation patterns are likely to increase the risk of water shortages in some regions whilst intense rainfall over a short period of time could lead to flooding. Adaption strategies to reduce risk of water shortages involve:
Adaptation strategies to increase risk of flooding include:
Figure 2. House in the Florida Keys, USA built on stilts to minimize flood damage.
Changes to agriculture practices to reduce impacts of climate change include:
Figure 3. Flooding of agriculture fields can kill crops.
To minimise the impacts of climate change on fisheries, other pressures need to be reduced to avoid collapse of fish stocks. This includes:
These changes may require fishermen to seek employment in other sectors.
Strategies to counteract the impacts of climate changes on ecosystems include:
Figure 4. Coral reefs contain high levels of biodiversity are under high threat from impacts of climate change.
Planning guidance needs to consider the impacts of climate change. It may include incorporating the management of rising sea level and increased storm surges. This could involve:
Figure 5. Groynes are used to break up waves hitting the coast line.
It has been predicted that the Carteret Islands off the coast of Papua New Guinea in the Pacific Ocean will be submerged by 2020. Its residents are being relocated to other areas such as Bougainville in Papua New Guinea.
Adaptation strategies to impacts of climate change on health involve:
Figure 6. Child being administered polio vaccination.
Change can take time but delaying decisions can increase rate of change and intensity of impacts. Hence we need to identify barriers to mitigation and adaptation in order to consider how to overcome these issues.
International-mindedness
Climate change affects everyone and therefore international collaboration to tackle the problem is necessary.
If we know what to do to reduce GHG emissions and to limit the impacts of climate change what is holding us back?
Political commitment to take action to reduce levels is driven by a variety of factors, for example:
Figure 1. Climate change campaign in New Zealand.
Even when a decision to take action is agreed, effective adoption of mitigation and adaptation strategies can be impeded by:
In order to overcome the barriers to mitigation and adaption there needs to be:
The impacts of climate change are not evenly distributed and some of the most vulnerable countries (e.g. low lying coastal areas such as Bangladesh) have the least resources making adaptation difficult.
Figure 2. The Ganges-Brahmaputra Delta is the largest delta in the world and sea level rise could result in millions of people becoming homeless.
The capacity to take appropriate action varies from country to country and is often limited in some developing countries by access to funds, technology and expertise. Hence it is necessary for wealthier nations to provide some of the most vulnerable and poorest countries with support to deal with climate change.
Watch the following video ‘Climate change adaptation: it’s time for decisions now’ and consider:
International cooperation and collaboration is vital for effective mitigation and adaptation at a global level. However, compliance to international environmental agreements often relies on good will and self-policing. Regional and national legislation are often more effective with clear monitoring and enforcement.
Figure 1. International cooperation allows groups to help each other to meet common goals.
Intergovernmental Panel on Climate Change (IPCC) was set up by the United Nations Environmental Programme (UNEP) and World Meteorological Organisation (WMO) in 1988. The aim of the IPCC is to provide a scientific view of the current knowledge and understanding of climate change and its impacts. The IPCC involves scientists and governments from across the world. Hence their work has wide ownership which can help to influence national policies.
The United Nations Framework Convention on Climate Change (UNFCCC) was signed by 154 nations during the Earth Summit in Rio in 1992. It came into force in 1994 with the aim of stabilizing atmospheric greenhouse gas levels by providing a framework for protocol agreements. Parties meet each year to discuss progress and set targets. These meetings included Kyoto in 1997 that led to the Kyoto Protocol.
The Kyoto Protocol which can into force in 2005 and set targets to control GHG emissions:
Figure 2. Emission targets for selected countries.
Amendments referred to as the Doha Amendment were made to the Kyoto Protocol in 2012 with targets of:
This amendment has yet to be accepted by a sufficient number of nations to come into force.
The UNFCCC requires less economically developed countries to produce a National Adaptation Programme on Action (NAPA) highlighting which areas are most vulnerable to climate change and where adaptation is most required. Selected projects are financially assisted (e.g. via the Least Developed Country Fund and Green Climate Fund).
Figure 3. Countries in which there are NAPA projects (2014)
Theory of Knowledge
To what extent was it ethically justified for developing countries such as China and India to be exempt from the Kyoto Protocol?