In this unit, we come full circle in our study of global environmental change by looking at human impacts and responses.  How will we be affected by global changes and how will we respond?  The answer to this question has profound implications for humankind and has significant socioeconomic and political meaning.

    Human impacts and responses are a cyclical process.  How individuals and society respond to global change, climatic change or otherwise, restructures the very actions that triggered the human component of that change in the first place.  For example, if stock farmers in the United States were forced by diminished vegetation cover (because of increased frequency of droughts, for instance) to send their stock onto steeper land to graze, the vegetation cover would decrease at an increasing rate, since the steeper slopes are more prone to erosion when vegetation is regularly removed.  Land deterioration on this scale affects the productivity of the agricultural market, which is reflected in food prices and quality.  Farmers would be economically as well as environmentally stressed and may be forced to make progressively more damaging environmental decisions.
 
    In the following section, we consider the ways in which we may respond to global environmental changes with a specific focus on global climate change.

Human Responses to Environmental Change

 

    The US National Research Council (NRC) has developed an analytical framework for understanding the possible human responses to global environmental changes (Stern, Young, and Druckman 1992).  Their framework includes:

• Responses to experienced versus anticipated change:  People and social institutions respond to environmental change both as it is experienced (after the fact) or as it is anticipated.  In the past, the former response tended to be more prevalent; however, with increasing scientific knowledge, anticipatory responses have become possible.
• Deliberate responses versus actions taken with incidental effects:  Some human actions can be taken as a deliberate response to environmental change.  For example, the building of dikes in coastal areas may protect some populations from rising sea levels.  On the other hand, some human actions may have incidental effects on environmental change.  A large tax increase on gasoline, enacted for a reason unrelated to global change, may have the incidental effect of reducing CO₂ emissions and slowing the pace of global warming.
• Coordinated versus uncoordinated responses:  Some human responses may be coordinated actions taken by governments or other organizations.  Other actions may be uncoordinated, such as those undertaken by individuals.

    Mitigation describes an action that prevents, limits, delays, or slows the rate of undesired impacts by acting on either the environmental system, the human proximate forces, or the human systems that drive environmental change.  Using climate change as an example, humans could intervene on the environmental system by blocking solar radiation with orbiting particles that reflect solar radiation.  Humans could also intervene on the proximate forces by regulating automobile use to control CO₂ emissions.  Lastly, humans could intervene in human systems by investing in research on renewable energy sources.

    Adaptation is another action that humans may undertake in response to environmental change.  Adaptation includes activities such as blocking or adjusting to environmental changes.  Blocking is an action that prevents the change from having an impact on a valued environmental system.  Unlike mitigation, blocking does not prevent the undesired event from occurring; rather it prevents it from affecting something that humans value.  For example, farmers may introduce drought resistant crops to block the effects of climate change on the agricultural system. Adjusting neither prevents a change from occurring, nor does it prevent it from affecting a valued environmental system.  Rather, an adjustment is a response to the occurrence of the change.  For example, humans may adjust to sea level rise by migrating away from low-lying coastal areas.

    A variation of adaptation is anticipatory adaptation in which actions are undertaken to improve the ability of social systems to withstand environmental change before it occurs.  For example, farmers may choose to diversify their agricultural systems by growing polycultures which may be more robust to the effects of environmental changes.  When climate change occurs, the risk of total crop failure and possible famine would be reduced as a result of the anticipatory action taken by the farmer.

    Now that we’ve looked at a general framework of responses to global environmental changes, let’s look at how the world has actually responded to the threat of global climate change.
 

International Responses to Climate Change

 

    Attempts to mitigate or intercede to reduce potential climate change are difficult because they involve different perspectives and values and they require compromise.  The policies that result have immediate economic, social, and political consequences.  For example, consider how difficult it would be to institute the automobile emissions-reducing plan of Mexico City whereby each car can not be used one day of the week, in a particular community.  Who would have objections and what might these objections be?

    The United Nations General Assembly established the Intergovernmental Panel of Climate Change (IPCC) to advise the world on the potential for climate change, its physical consequences, and the likely effects of various responses.  One of the central questions is the cost effectiveness of strategies aimed at reducing greenhouse gases to stave off climate change versus strategies that assist humankind to adjust to the new conditions (Nordhaus 1992; Rosenberg and Crosson 1991).  The answers, of course, are too full of uncertainties to command authority.  What is clear from most assessments is that there will be winners and losers (Rosenzweig and Hillel 1993); some areas of the world will benefit from climate change and others will suffer negative impacts.  Given the regional differences in environmental changes that are projected and the regional differences in the ability to adjust (e.g., developed vs. less developed parts of the world), the regions of the world already suffering from poverty and other problems (in other words, those areas that are most vulnerable) seem the most likely to bear the brunt of climate change impacts.

    The IPCC notes that human interventions may occur at many different points in the four-box illustration shown at the beginning of each unit of this module.  The IPCC also emphasizes the pivotal role of conflict in the assessment and selection of intervention strategies -- not only because intervention strategies have variable consequences for variable interests (e.g., current industrial activity, tax policies, or developing world farmers) but because intervention or the lack of it involves human values in different ways.  These themes are illustrated in the example below.

    At the United Nations Conference on Environment and Development (UNCED) meeting in Rio de Janeiro in 1992 known as the Earth Summit, 167 nations signed the Framework Convention on Climate Change (FCCC) with the aim of reducing greenhouse gas emissions and therefore the risk of global warming.  Each nation was required to prepare a climate action plan identifying the major sources of greenhouse gas emissions within their country and ways of reducing them.

    In 1995, the Berlin Climate Summit provided the first chance since the Earth Summit for governments who signed and ratified the FCCC to commit themselves to further reduction of greenhouse gases.  Only countries who have ratified the Convention now have the right to participate in the on-going, formal decision-making process.  Debate continues about whether the reduction of emissions committed to by the ratifying countries will be sufficient to stabilize CO₂ levels in the atmosphere.

    Both the Rio and Berlin Summits produced interesting sets of alliances and agendas among countries.  At least three major groupings emerged:  the developing South, the industrialized North, and the “energy” export countries.  The North-South distinction refers to the prevalence of developed countries in the northern hemisphere (primarily north of 30^o latitude), and developing countries in the southern hemisphere.  Table 2 lists a few of the developing and developed countries based on a “Human Development Index” (HDI) created by the United Nations.  The HDI combines three indicators of economic development:  per capita purchasing power, life expectancy at birth, and literacy rate.  The minimum for each of the indicators was set at the lowest level observed in any country.  The maximum levels were 100% for literacy, the maximum observed life expectancy in any country, and the official poverty level in nine relatively developed countries (Rubenstein 1992).

    The perspective of the developing South, which has the least ability fiscally to adapt, is that climate change is a problem that has been produced by the industrialized North.  High levels of production and consumption in developed countries have contributed the highest amounts of greenhouse gases to the atmosphere, and therefore those countries should take the first steps on reducing emissions.  The countries of the North, however, are not interested in efforts to reduce emissions that will affect their economies, and their populations are not keen on reducing consumption habits.

    The countries of the industrialized North recognize their role to date in greenhouse gas emissions and have the greatest ability not only to reduce these emissions but to adapt to climate change.  Reducing greenhouse gases, however, has enormous consequences for the economies of the North.  No country wants to agree to policies that will negatively affect their own industrial base.  For this reason, the North is more likely to point to population increases in the South as the larger problem because the exponential population growth there makes the development transition more difficult (although this claim is disputed by some).

    Energy exporting countries have not favored the convention to reduce greenhouse gases because to do so would, they believe, drive down the use of fossil fuel energy and negatively affect their own economies.

    The general lessons here are repeated elsewhere in regard to global change either in individual or collective responses:

• we seek to protect our own behaviors not change them, especially when change is perceived to have negative impacts on our lifestyles;
• and we seek to find solutions in the behavior of others.

Conclusion

 

    Throughout this module we have explored global environmental changes and the ways that humans have contributed to these changes.  In particular, we’ve seen how human activity has altered terrestrial ecosystems and affected the global climate.  We’ve also seen how humans have responded to the changes that they have produced.

    Consider for a moment that the changes in climate predicted by the IPCC will take place during your lifetime.  By the time your children are in college, the global annual mean temperature is predicted to have increased by 2^oC and sea levels are predicted to have risen by 50 cm.  What will this mean for your life and your children’s lives?  Will you be one of the “winners” or one of the “losers”?  If we are unable to prevent further global environmental changes and respond effectively to those that are already underway, won’t we all be the “losers”?