The fourth section of the Copenhagen congress synthesis report is firmly in the realm of policy. Addressing climate change involves ethics.  Unequivocally the report asserts that serious equity issues should inform the fight to restrain global warming and enters into detail in identifying them.  For one thing the climate is not changing uniformly around the world and the human effects are unequal. Profoundly unequal, for example, in the impacts of climate change on health. The poor, the marginal, the uneducated and the geographically vulnerable are at greatest risk of injury and death. In general, developed countries are most responsible for climate change up to now while developing countries suffer the majority of the impacts. Any lasting and widely accepted solution to the climate change challenge should recognise and account for these equity dimensions in negotiations and agreements.
Questions of ethics and justice are key factors in adaptation approaches. The report focuses on the responsibility for financing adaptation in many developing areas of the world affected by poverty where there may simply not be the capacity to take adaptive measures. We need better analysis and research of such matters as water scarcity and food shortages which would enable identification of the people and places most vulnerable and enable resources to be directed towards reducing those vulnerabilities.
Equity issues have temporal as well as spatial dimensions. The report claims there is now general agreement that standard economic approaches employing standard cost benefit analysis and standard discounting are not adequate to intergenerational equity when it comes to climate change.  A business-as-usual approach is unjust to future generations, who have a fundamental right to an environment they can live in.
The unfolding biodiversity catastrophe raises not only concerns about the provision of ecosystem services to humans, but also ethical issues regarding the relationship between humanity and the rest of nature. The potential extinction of charismatic species or iconic ecosystems, such as coral reefs or rainforests, as a consequence of climate change is regarded as unacceptable by many people.
Equity matters for mitigation of climate change, and invariably enters discussions of differential responsibilities for emission reductions across countries. The scientific basis for the equity dilemma regarding mitigation is the so-called stocks and flows problem. The climate responds to the amount of greenhouse gases in the  atmosphere –- the stocks. Because of the long lifetime of CO2 and some other greenhouse gases in the atmosphere, the stocks are dominated by the historical emissions from developed countries. Thus, the level of climate change being experienced in 2009 is largely caused by the historical emissions from wealthy countries. Although the rate of increase in emissions from developing countries is now increasing rapidly, on a per capita basis developed countries still dominate emissions and will continue to do so in the foreseeable future. For example, in the USA, per capita emissions are over 20 tonnes, in the Nordic countries about 11 tonnes, and in China under 4 tonnes. Within national contexts also, mitigation approaches invariably intersect with structural inequalities in complex ways, often to disadvantage economically and politically weaker sub-populations. This must be addressed.
The development and deployment of low- or no-carbon technologies raise equity issues especially for developed-developing country interaction. The report suggests ways in which developed countries should ensure that technologies are shared, including  explicitly planning for spill-over and diffusion to developing countries when demonstration projects are carried out in a developed country.
Strategies to reduce emissions from deforestation and forest degradation need to be equitable, especially in protecting the rights of forest-dependent populations. Â
Biology-based mitigation approaches include the development and use of biofuels. These involve equity considerations, as can be seen from the 2008 spike in food prices, which was at least in part attributable to competition with biofuels for land.
The section concludes that equity issues pervade virtually all aspects of the climate change challenge. The twin challenges of the 21st century –- avoiding dangerous climate change and poverty alleviation –- should and can be tackled together. This sentence echoes Nicholas Stern’s affirmation in his recent book.
The synthesis report intended to provide not only a picture of where the science is now but also of the response options available to tackle the issue. The message to those negotiating in December is that a decent concern for equity will open up real opportunities for lasting global cooperation.