Humans have proven themselves to be a very adaptable species in both historical and recent times. We have migrated across the world and thrived in lands whose climates and resources we had no experience of. We have lived through epidemics of infectious diseases, wars, and resource scarcity. We have responded to natural climate variability and natural disasters through measures such as crop diversification, water management, irrigation, and risk management and insurance. Yet the situation facing us today appears unprecedented in recorded history, and the weight of evidence suggests that our interference with the climate system may result in dangerous consequences.
In response to this risk, we are faced with two options: mitigate or adapt. In practice, both of these approaches will be required in our strategy to deal with climate change.
Humans have already significantly altered the composition of the atmosphere through emissions of greenhouse gases from activities such as burning of coal and oil. This has changed the heat balance of the planet and led to a measurable increase in global surface temperature. Some of the processes involved in exchanging heat and energy in the earth-climate system operate on long timescales. For example, overturning of deep ocean water, and therefore redistribution of heat and carbon dioxide in the oceans, takes thousands of years. This means that the system is not in equilibrium, and sea levels and ocean acidification will continue to increase even if atmospheric greenhouse gas concentrations are stabilised at today’s levels. Associated changes in circulation patterns and temperature will also continue. In essence, further climate change is inevitable.
We will therefore need to develop strategies for adaptation. However, our capacity to adapt is not limitless, and we will also need to develop and implement aggressive strategies for mitigation of climate change. There are many possible technological approaches, some of which we detail in this section of the web site. For example, reducing emissions of greenhouse gases may be achieved by energy conservation, by improving our coal-burning technologies, and by the use of non-carbon energy sources (renewable and nuclear energies) and alternative transport fuels. Other technological mitigation options include the sequestration of carbon by various means, and possible geoengineering solutions that have been suggested.
Mitigation will not be an easy task, and may require incentives to make these options economically viable. The pages on economic responses detail the options for setting up an economic framework to support policy mitigation goals. These include carbon taxes, emissions trading, sustainability reporting, and tax deductions for carbon sink forests.
Planning for climate change is a challenge unlike any we have faced before. Because of this, our response will need to be flexible, to adapt to changing circumstances and ongoing analysis. However, studies from both scientific and economic perspectives suggest that even if our initial strategies are not optimal, early action will minimise the costs of mitigation as well as the risks of dangerous climate change.