Field - David Marcu

Climate Action

What do we need to do to address the problem of climate change? It is a complex problem that was hundreds of years in the making. Furthermore, almost all aspects of our daily life are in some way connected to the causes of climate change – energy production, food production, transportation, and the manufacture and shipping of all the goods we buy and use. It is easy to feel overwhelmed. Fortunately, there are many things we can do, individually and collectively, to help reduce the scale of the problem and to prepare ourselves for a changing world.

Climate action generally falls into two categories, mitigation and adaptation. The goal of mitigation is to limit the total warming of the climate system by reducing greenhouse gas (GHG) concentrations in the atmosphere, either by reducing our emissions or by enhancing natural or artificial processes for removing GHG from the atmosphere. Adaptation involves preparing ourselves, our communities, and our environment for inevitable change in order to minimize the costs, or even to take advantage of opportunities that might arise from change. Since adaptation strategies vary widely from one region to the next, we will focus our discussion on mitigation.  To get started, expand the blue bars below.

References: All scientific claims here are supported by strong evidence in the peer-reviewed scientific literature.  Rather than list literature citations, we refer to relevant passages in the UN's IPCC reports. The UN's Intergovernmental Panel on Climate Change (IPCC) issues regular Assessment Reports (AR). These reports are surveys of the literature on climate change and its impacts.  They will guide you through the evidence and refer you to the original publications. For example, "AR5 WG1 1.2.2" is a reference to Section 1.2.2 in Working Group I's contribution to Assessment Report 5. For links to the IPCC reports, see our list of Additional Resources.


Identifying appropriate goals for mitigation is a complex and controversial problem, but for the sake of comparing different forms of action, the IPCC uses a benchmark goal of limiting the increase in average global surface temperature to 2°C by the year 2100. While this may seem like a modest increase, it would in fact result in significant and costly changes to ecosystems and many human systems. These changes and their likelihood are analyzed in AR5’s Working Group II report on Impacts. This goal in turn implies that we would need to pursue a Representative Concentration Pathway comparable to RCP2.6 or RCP4.5. These pathways give us possible scenarios for changes in greenhouse gas (GHG) concentrations throughout the 21st Century, as analyzed in Working Group I’s report on the Physical Science Basis. Reviewing these pathways, we see that both assume that GHG concentrations will level off or decline before the end of the century. They differ in terms of how soon this must happen. RCP2.6 assumes that CO2 concentrations peak by 2050 and thereafter decline, whereas RCP4.5 assumes that CO2 concentrations peak by about 2075 and thereafter remain steady for the rest of the century.

What is the relationship between atmospheric concentrations and emissions? Carbon dioxide is removed from the atmosphere through a variety of natural processes. It is absorbed by vegetation and the oceans, and it is transferred directly from the air to the rocky surface of the earth via a process called chemical weathering. In addition, GHG that remain in the atmosphere can undergo chemical reactions with other gases and break down over time. The atmospheric lifetime of CO2 typically ranges from thirty to a hundred years, although about 20% of CO2 remains in the atmosphere for many thousands of years. Methane is a much more potent GHG, but its atmospheric lifetime is much shorter, around ten years. (See AR5 WG1 Chapter 6 for a full explanation of the life cycles of greenhouse gases.) We are currently emitting GHG into the atmosphere faster than they are removed from the atmosphere, so even if we stabilize or slightly reduce our emission rates, concentrations will continue to rise. Think about the fact that if water is flowing into a tub much faster than it flows out, then even if we slightly reduce the rate at which it flows in, the water level will continue to rise. If we must stabilize or reduce concentrations, then we must reduce our emissions much more significantly.

Unfortunately, emissions have been increasing, and in fact at a faster and faster rate. The AR5 Working Group III report on Mitigation documents emissions through 2010. About half of all emissions within the period of 1750 to 2010 occurred in the last forty years. The biggest increases in emissions occurred in the period 2000-2010. The biggest drivers of these increases in emissions rates are population growth and economic development. [AR5 WG3 5.2, 5.3]

In order to steer ourselves onto a concentration pathway like RCP2.6 or RCP4.5, we will need to reduce GHG emissions significantly over the course of the century, even while our population continues to grow. While we can expect improvements in technology to lead to greater efficiency, this trend alone will not be sufficient to achieve the necessary emissions reductions. [AR5 WG3, 5.6] We will need to transform our practices both individually and globally, across large economic sectors. Furthermore, since there is a significant time lag between reducing emissions and reducing or stabilizing atmospheric concentrations, any delay in reducing emissions means higher concentrations for a greater portion of the century, hence greater total climate warming by 2100. Reducing emissions now results in a very different scenario from waiting and reducing emissions by the same amount in fifty years.

Sources of GHG emissionsThere are many sources of anthropogenic (i.e. human-caused) GHG emissions. The largest source is fossil fuel combustion for energy production and transportation; the primary GHG output is CO2. Another large category of emissions sources is often referred to as AFOLU for Agriculture, Forestry, and Other Land Use. Emissions from these two categories as well as other industrial processes (e.g. cement production) are shown in the graph. GHG emissions are given as CO2 equivalent emissions in gigatons. (Since the various GHG have differing greenhouse potency, it is helpful to give a single quantity, in gigatons, that represents the amount of CO2 that would produce the same total radiative forcing as all of the emitted greenhouse gases together.)

The categories of emissions sources analyzed in AR5 WG3 are energy production, transportation, construction, industry, AFOLU, and waste generation. See AR5 WG3 5.3 for a summary, and Chapters 7-12 for detailed analyses of mitigation options within each category.

Who is responsible for these emissions? There are two ways to attribute GHG emissions to particular countries or regions. One is to determine the total quantity of GHG emitted within that region (territorial emissions). The other is to determine the total quantity of GHG emitted globally as a result of consumption within that region (consumption-based emissions). See AR5 WG3 Box 5.2 for a discussion of these two forms of attribution. For example, improvements in technology and regulation, and a shift from coal to natural gas, have slightly moderated territorial emissions within the US; however, Americans continue to have very high levels of consumption, especially of goods manufactured elsewhere, so our consumption-based emissions continue to rise. Another consideration is that in some developing countries, individual consumption is still quite low (due to a combination of poverty and cultural practices, such as diet and a tendency to reuse and recycle materials), even though the total emissions rate is high due to a large population. Thus it is meaningful to determine per capita (i.e. per person) emissions. In 2010, the median per capita emissions for low income countries was 1.4 tons CO2 equivalent per person, whereas the corresponding figure for high income countries was 13, almost ten times higher. [AR5 WG3 5.2.1]

GHG emissions tend to follow economic activity. For example, emissions dipped slightly in 2009 as a result of the global recession that began the year before. In general, when people lack economic resources, they use less electricity and buy fewer goods, resulting in reduced emissions. While economic recessions and poverty are not healthy approaches to climate action, this demonstrates that reductions in individual consumption do translate into reductions in GHG emissions. See AR5 WG3 5.5 for extensive evidence of the impact of behavioral choices on consumption and emissions. Switching to renewable energy sources, increasing energy efficiency, transforming our agricultural practices, and reducing livestock production can also result in emissions reductions. It will take a combination of action of all these types to achieve our mitigation goals.

Climate engineering or geoengineering refers to a wide variety of forms of intervention in the climate system designed to artificially remove CO2 or other GHG from the atmosphere or to reduce the amount of solar energy reaching the earth’s surface. While scientists and entrepreneurs are currently researching many forms of climate engineering, these are all in a very early and speculative stage of development, and additionally they carry significant risks of side effects and unintended consequences. In addition, some of these technologies, if developed, could potentially be weaponized and used by governments or rogue parties to cause considerable damage to the atmosphere and the biosphere. These costs and risks need to be considered alongside the potential benefits. [AR5 WG3 6.9]

Climate engineering generally falls into two categories, carbon dioxide reduction (CDR) and solar radiation management (SRM). An example of CDR technology would be artificially seeding giant blooms of algae or phytoplankton in the ocean; the organisms would absorb CO2. One of the most promising forms of CDR technology is carbon capture and sequestration (CCS), which involves removing CO2 at points of emission, such as power plants, and storing it. Both the removal and storage aspects of this process present technical challenges that have not yet been overcome, and such technology is likely to be very expensive to implement on a large scale. However, CCS does not carry some of the environmental and political risks associated with other forms of climate engineering. [AR5 WG3 6.9.1]

The costs and risks associated with SRM technologies are even more concerning. Various ideas have been proposed, such as detonating material into the atmosphere to seed cloud cover, or installing large shade panels in space. In addition to the environmental and political risks, these technologies do nothing to address ocean acidification from elevated atmospheric CO2 concentrations and the resulting damage to ecosystems and the food chain. [AR5 WG3 6.9.2]

If we were to implement any forms of climate engineering instead of reducing our emissions, then we would need to commit to them, including their costs and risks, forever; if we ever ceased or scaled back the intervention, say during a period of conflict or economic recession, we would see an immediate rise in GHG concentrations. Despite all these concerns, this is an important area of continuing research, and a suitable form of climate engineering may eventually constitute part of our response to the problem. In the meantime, it would be foolish to delay pursuing emissions reductions based on the hope that climate engineering will make this unnecessary. [AR5 WG3 6.9]

What are changes that we as individuals can make to reduce our contribution to GHG emissions? This contribution is often called an individual’s carbon footprint. One way to identify opportunities for change is to consider how our lives are different from those of a few generations back, when individuals even in developed economies had much smaller carbon footprints. Back then, many families did not own a car. People were more likely to walk or use public transportation when they needed to go somewhere, and they traveled less. Today, most of us expect to drive our own cars around our communities and to travel by car or plane on a regular basis. This has obviously improved our quality of life in many ways, but it has come at a cost. Today our lives are filled with labor-saving appliances, such as dishwashers, washing machines and dryers, electric can openers, microwave ovens, lawnmowers and other motorized lawn tools, etc. This allows us to spend less time and effort on housework, but it comes at a cost. In addition to the carbon cost of our reliance on car transportation and labor-saving devices, we lead more sedentary lifestyles today with resulting costs to our health and comfort. Are there ways to reduce our carbon footprint while maintaining or improving our quality of life? A good motto is, “Burn calories, not fossil fuels.”

One of the main ways in which our lives are different today is the sheer amount of stuff that we purchase and use – and often discard after only one use. Everything we buy was grown or manufactured using energy and raw materials, and then shipped to us. Those raw materials had to be taken out of the earth and transported. All of these activities contribute to GHG emissions. Buying less, reusing more, repairing things rather than replacing them, and reducing the amount of packaging associated with our purchases can all reduce our carbon footprint. If we’re thoughtful about it, we can greatly reduce our consumption of goods without compromising our quality of life in any essential way. See AR5 WG3 and 5.4 for an analysis of the impact of consumption patterns and trade on emissions.

Switching to renewable energy will be a crucial part of our response to climate change. Some of us can make this change on an individual basis by installing solar panels on our residences and businesses, or by investing in a shared solar installation in our community. In New York State there are various aids (cash incentives, tax credits, and low-rate financing) that greatly reduce the cost of solar installations. In addition, the resulting savings on electricity means that the cost of the installation will often be paid back after only a few years. To learn more about the costs and benefits of going solar in New York State, see this NYSERDA website.  If you are unable to install solar panels on your property, you might be able to switch to renewable energy through the grid. What this means is that your electricity provider agrees to obtain a certain proportion of the electricity on the grid from renewable sources, which helps to support and incentivize investment in renewable energy. You can also advocate at the state and federal level for investment in renewable energy development and infrastructure, as well as economic policy and regulation that favor the renewable energy sector. See AR5 WG3 7.5.3 for more information on the mitigation potential of switching to renewable energy, and Chapter 7 more generally for a full analysis of emissions trends and mitigation in the energy sector.

Increasing energy efficiency is an important part of our response. When you’re ready to purchase a new car or appliance, look for energy efficient models. Consider getting an energy audit conducted on your home or business to identify ways to improve efficiency. When you’re planning new construction or a renovation of your property, investigate ways to improve energy efficiency, as well as to reduce the carbon footprint of the process by reusing old material and considering the source of new material. Keep in mind that every new purchase comes at a considerable carbon cost. It often takes several years before the carbon savings of a new energy-efficient car or appliance compensates for the carbon cost of manufacturing and shipping it. Only buy new if you’re sure that there’s a net carbon cost reduction. Better yet, consider whether you could make changes to your lifestyle so that you could do without the item without compromising your quality of life. See AR5 WG3 7.5.2 for more information on the mitigation potential of improving efficiency in energy production.

Livestock production accounts for about 14% of all GHG emissions, according to a UN FAO report. The same report suggests that this could be reduced by about 30% by adopting existing climate smart technology and practices across the industry. You can reduce your carbon footprint by reducing or eliminating your consumption of meat and dairy, or by buying them from farmers who use those climate smart practices. See AR5 WG3 Chapter 11, especially sections 11.2 and 11.3, for a full analysis of emissions and mitigation options associated with food production, including livestock production.

We can also reduce our carbon footprint by composting food waste rather than burying it in landfills. A landfill is an anaerobic environment (one with little or no oxygen in its gaseous form), and anaerobic decomposition produces primarily methane. An above-ground compost bin is an aerobic environment (one with gaseous oxygen), and the primary result of aerobic decomposition is carbon dioxide. While both are greenhouse gases, methane has a significantly more powerful greenhouse effect. If you can’t compost on your own property, find out whether your community has shared or municipal composting. See AR5 WG3 10.14 for a full analysis of trends in GHG emissions due to waste generation and management, and options for mitigation.

We have seen examples of the kinds of changes we can make as individuals to reduce our carbon footprint. If only a few people make these changes, it won’t have much impact. But if lots of people act, and if businesses and corporations take action, the impact would be considerable. How do we bring about widespread action? One way to start is to talk to people about climate change and climate action, both in person and on social media. However, in general, people are reluctant to take action that they perceive to be inconvenient or costly. Businesses are likely to be unwilling to take action if their competitors are not doing likewise, as that might put them at an economic disadvantage.

The most effective way to incentivize change is to make people and businesses more aware of the true costs of their current practices. In economics, a cost is external to the market if it is not born by those who engage in the transaction. When we emit GHG into the atmosphere as a result of any number of practices (e.g. fossil fuel combustion for energy production), the costs are born by other people in the world who did not benefit from this and also by future generations. In unregulated markets, prices are determined exclusively by the parties who engage in transactions, and it follows that external costs are generally not accounted for in the market price of goods and services. Thus we are inclined to discount or ignore external costs, and leave them for others to bear. We make decisions, individually and collectively, based on market price, and as a result these are often very poor decisions with regard to addressing climate change.

There are various ways to internalize the costs of GHG emissions, i.e. to intervene in the market so that market prices more accurately account for total and long term costs. These typically take the form of economic policy (e.g. carbon taxes, cap and trade structures, and industry subsidies) or industry regulation (prohibiting environmentally costly practices or imposing a financial penalty on those who engage in them). Most of these approaches have the effect of raising the cost of some goods and services. This higher cost is a more accurate reflection of the total costs of doing business, including the short and long term environmental costs. The most important consequence is that individuals and businesses are motivated to make the transition toward climate smart practices. Such measures carry risks of economic downturn and unemployment, especially for periods of short term transition. See AR5 WG3 15.3 for a full analysis of the risks and benefits of economic, regulatory, and other policy approaches. Ultimately, we need to determine how much short term economic risk we are willing to accept in order to address the long term problem of climate change.

The most direct method of adjusting market price is a carbon fee or carbon tax. This might take the form of a tax that is collected at the state or national level, and the revenue generated by this tax might be directed toward offsetting the costs of mitigation and adaptation, such as investing in renewable energy infrastructure or building retaining walls to protect coastal cities from rising sea levels. The tax might be levied on individuals, or it might be levied on businesses and corporations which then pass the burden on to customers in the form of higher prices. The Citizens’ Climate Lobby proposes a “Carbon Fee and Dividend” on businesses that directs much of the generated revenue back toward businesses and industries in order to offset any resulting economic drag.

Another strategy for incentivizing change at high levels, internationally or across large economic sectors, is a cap and trade or emissions trading structure. This puts a cap (an upper limit) on total GHG emissions for each participating party (for example, countries or businesses), and then allows a party to buy the right to exceed its cap from another party, whose cap is then lowered. For example, the European Union has a cap and trade structure that puts a cap on large companies’ emissions. A company that has already invested in lowering their GHG emissions rates can then profit from their foresight by selling emissions rights to another company. By contrast, a company that is unable to stay under its emissions cap without significant financial trauma can buy the right to exceed it. The result is that overall emissions targets are met while allowing individual parties some freedom in determining how best to balance their emissions and financial goals. In the US, the Regional Greenhouse Gas Initiative (RGGI) is a cap and trade system among power plants in northeast and mid-Atlantic states, and California has a cap and trade system involving businesses in the power production, manufacturing, and transportation sectors.

So far our discussion has focused on the costs of implementing and incentivizing climate action. However, every challenge also presents us with opportunities for benefits and growth, and climate change is no exception. The last decade has seen tremendous growth in the renewable energy sector and the industries that support it, such as manufacturers of solar panels, electric and hybrid transportation, and batteries. A 2017 economic report shows that jobs in the solar and wind industries are growing twelve times faster than the US national average, and the solar industry now employs more people than coal, oil, and gas combined. Entrepreneurs are hoping to profit from their investments in climate smart technology and business models. The transition to renewable energy and more climate friendly forms of food production will also reduce air and water pollution and improve public health. Each of Chapters 7-12 in AR5 WG3 has a section on the co-benefits of mitigation within each sector.

Do One Thing campaign

The Alliance for Climate Education (ACE) has created a campaign called Do One Thing (DOT) which encourages people to commit to one climate action at a time.  You can participate by entering your DOT at their website, where they also have extensive materials aimed at young people and educators.  Here at CEI we have created our own list of accessible climate actions that you can choose from.  Challenge yourself to Do One Thing, and encourage others to step up, too.


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