Triangle diagram from the IPCC Forth Assessment Report (Chapter 18) describing the relationship between adaptation, mitigation, and inaction. (Image: IPCC AR4)
In general, there are two different strategies when it comes to dealing with climate change. We can try to stop future warming (mitigation of climate change) or we can find ways to live in our warming world (adaptation to climate change).
- Adaptation involves developing ways to protect people and places by reducing their vulnerability to climate impacts. For example, to protect against sea level rise and increased flooding, communities might build seawalls or relocate buildings to higher ground.
- Mitigation involves attempts to slow the process of global climate change, usually by lowering the level of greenhouse gases in the atmosphere. Planting trees that absorb CO2 from the air and store it is an example of one such strategy.
Of course there is a third option: to do nothing.
The triangle diagram to the left sums these options. It is from the IPCC Fourth Assessment Report (Chapter 18). The corners of the triangle represent 100% of each of these three options. Areas in the middle of the triangle represent a combination of approaches. There are costs associated with mitigation and adaptation. However, notice that with no action, we are facing a high cost associated with climate impacts because we will be ill prepared to deal with impacts.
It’s quite unlikely that we will be able to clean up the extra greenhouse gases and halt climate change entirely through mitigation efforts. Thus, some adaptation will be necessary. Both adaptation and mitigation are essential to reduce the impacts of climate change. Strategies to mitigate and adapt to climate change range from an individual, to local, national and global efforts.
Adaptation: making changes that enhance resilience or reduce vulnerability to changes in climate
Humans have a long history of making changes in the way they live to survive environmental changes. We are pretty industrious. These changes are ways to adapt to new conditions. Adaptation of human societies to climate change is taking place today on a limited basis. Current climate change poses challenges to adaptation.
Adaptation happens in a variety of ways. Some adaptations are fueled by changes in government policies. Other adaptations occur because of technological advances. (And there are, of course, ways that we individually adapt (insulating the attic to keep cool during summer heat waves or raising and reinforcing a house in a hurricane-prone area).
Advances in climate modeling have provided scenarios of future impacts, which are driving some of adaptation efforts that will hopefully reduce vulnerability to climate change. However, the ability to adapt is not equal between all people, states the IPCC (Working Group II). For example, developing nations with limited resources that are already dealing with the stresses of violent conflicts or high HIV/AIDS rates are less able to adapt to climate change. This is especially problematic in places like southern Africa where the impacts of climate change on drought conditions are expected to become increasingly severe.
There are limits to how much we can adapt. There are often technological and financial limits that prevent the scale of adaptation that we would need. And often people are unwilling to change their behaviors. Plus, while humans may have the ability to adapt to climate change, many other species may not.
Take a look at the table in Examples of Adaptation Practices (from the IPCC Fourth Assessment Report). It provides examples of adaptation initiatives by region, undertaken relative to present climate risks, including conditions associated with climate change.
Mitigation: making changes to slow climate change by lowering the amount of greenhouse gases
There are two ways to stop increasing the amount of greenhouse gases in the atmosphere. You can stop putting so many greenhouse gases into the atmosphere. You can also invent ways to get greenhouse gases out of the atmosphere – for example, planting trees that absorb CO2 from the air is an example of one such strategy. These two methods are usually thought of in combination.
Reduction of the amount of greenhouse gases put into the atmosphere (i.e, greenhouse gas emissions) is usually accomplished through reducing energy use and switching to energy sources that don’t release greenhouse gases. Frequently discussed energy conservation methods include increasing the fuel efficiency of vehicles, making individual lifestyle changes, and changing business practices. Technologies such as hydrogen fuel cells, solar power, tidal energy, geothermal power, and wind power, along with the use of carbon sinks, carbon credits, and taxation, are aimed at countering greenhouse gas emissions more directly.
Some ideas are easy and inexpensive, such as replacing incandescent lights with compact fluorescent bulbs that use less electricity than their conventional counterparts. Many mitigation techniques, such as fuel cells and biofuels, are still in the development phase and will require further research to determine their usefulness and viability. Some proposals, such as seeding the oceans with iron to increase phytoplankton populations (and draw more CO2 out of the air), sound more like science fiction and are unlikely to be implemented, especially when we don’t fully know the consequences for marine life.
There doesn't appear to be a shortage of steps that we can take to reduce our carbon emissions, but there is no single fix. The table below lists technologies that are currently available or are expected to become available within the next 25 years and would be implemented at the scale of governments, communities, and industries. Some of the technologies in the table may be associated with other environmental concerns (e.g. increased uranium mining and nuclear waste storage required by nuclear power plants).
Key mitigation technologies and practices currently commercially available
Key mitigation technologies and practices projected to be commercialized before 2030
Improved supply and distribution efficiency; fuel switching from coal to gas; nuclear power; renewable heat and power (hydropower, solar, wind, geothermal and bioenergy); combined heat and power; early applications of Carbon Capture and Storage (CCS, e.g. storage of removed CO2 from natural gas).
CCS for gas, biomass and coal-fired electricity generating facilities; advanced nuclear power; advanced renewable energy, including tidal and wave energy, concentrating solar, and solar PV.
More fuel efficient vehicles, including hybrid vehicles, cleaner diesel vehicles, & biofuels. Shifting from road transport to rail and public transport systems. Increased non-motorized transport (cycling, walking, etc.). Improved land-use and transport planning.
Second generation biofuels; higher efficiency aircraft; advanced electric and hybrid vehicles with more powerful and reliable batteries.
Efficient use of lighting and daylighting. More efficient electrical appliances and heating & cooling devices. Improved cook stoves, insulation, and passive & active solar design for heating & cooling. Increased use of alternative refrigeration fluids and recovery & recycle of fluorinated gases.
Integrated design of commercial buildings including technologies, such as intelligent meters that provide feedback and control; solar PV integrated in buildings.
More efficient end-use electrical equipment. Improved heat and power recovery; material recycling and substitution; control of non-CO2 gas emissions; and a wide array of process technologies used in industry.
Advanced energy efficiency; CCS for cement, ammonia, and iron manufacture; inert electrodes for aluminum manufacture.
Improved crop and grazing land management to increase soil carbon storage; restoration of cultivated peaty soils and degraded lands; improved rice cultivation techniques and livestock and manure management to reduce CH4 emissions; improved nitrogen fertilizer application techniques to reduce N2O emissions; dedicated energy crops to replace fossil fuel use; improved energy efficiency.
Improvements of crops yields.
Improved afforestation (the establishment of a new forest by seeding or planting on nonforested land); reforestation; forest management; reduced deforestation; harvested wood product management; use of forestry products for bioenergy to replace fossil fuel use.
Tree species improvement to increase biomass productivity and carbon sequestration. Improved remote sensing technologies for analysis of vegetation/ soil carbon sequestration potential and mapping land use change.
Increased landfill methane recovery; waste incineration with energy recovery; composting of organic waste; controlled waste water treatment; recycling and waste minimization.
Biocovers and biofilters to optimize CH4 oxidation.
Table: Key mitigation technologies and practices by economic sectors. Sectors and technologies are listed in no particular order.
Adapted from Table SPM.3 in the IPCC AR4 WG3 Summary for Policymakers.