more frequent and extreme weather events. Higher atmospheric concentrations of carbon dioxide also lead to ocean acidification and affect the composition, structure and functionality of ecosystems. Time is running out to prevent irreversible and dangerous impacts of climate change. Unless greenhouse gas emissions are radically reduced, the world is on course to exceed the temperature threshold set out in the Paris Agreement under the United Nations Framework Convention on Climate Change. That makes climate change a global driver of environmental, social, health and economic impact and heightened society-wide risks. {2.7.3}


Society-wide risks associated with environmental degradation and climate change effects are generally more profound for people in a disadvantaged situation, particularly women and children in developing countries (established but incomplete). Many of the impacts outlined above are serious or irreversible and may lead to loss of livelihood, increased morbidity and mortality, and economic slowdown, and have greater potential for violent conflict, human mass migration and decreasing social resilience. Measures for more effective adaptation are now urgently required, especially for populations and regions which are in a vulnerable situation. {2.7.3}


The increasing scale, global reach and speed of change in those drivers of environmental change pose urgent challenges for managing environmental and climate change problems (well established). In many domains, our scientific understanding of adverse, increasingly high impact is becoming more widespread, as is the understanding that the nature of change may sometimes be irreversible. The thematic priorities addressed by GEO-6 have been chosen and analysed with that context in mind and the summaries by theme have been organized to provide decision-makers with the most crucial insights within themes, including links to drivers and optional avenues for action. {2.7.3}


2.2 The state of the environment 2.2.1 Air


Emissions generated by human activity continue to alter the composition of the atmosphere, leading to air pollution, climate change, stratospheric ozone depletion and exposure to persistent, bioaccumulative and toxic chemicals (well established). {5.3}


Air pollution is the main environmental contributor to the global burden of disease, leading to between 6 million and 7 million premature deaths (well established) and welfare losses estimated at US$5 trillion annually (established but incomplete). Air pollution exposure, especially to fine particulate matter, is highest for urban residents in some countries with rapid urbanization trends (established but incomplete) and for the approximately 3 billion people who depend on burning fuels such as wood, coal, crop residue, dung and kerosene for cooking, heating and lighting (well established). The elderly, very young, ill and poor are more susceptible to the impact of air pollution (well established). {5.2.4, 5.4.1}


Globally, decreasing emission trends from local air pollutants in certain sectors and regions have been offset by larger increases in others, including some rapidly developing countries and areas of rapid urbanization (well established). Available data


indicate that emissions decrease significantly when regulations are put in place. {5.2} International agreements have been successful in addressing specific chemicals. Both improvement of energy efficiency and pollution control techniques may be used to achieve lower air pollutant emissions. As controls have been placed on power plants, large industrial facilities and vehicles, the relative contribution of other sources, including agriculture, domestic fuel use, construction and other portable equipment, and forest or open fires, has grown in importance (established). Electricity generated from non-renewable resources and the fossil fuel production and consumption sectors (“energy”) is the largest anthropogenic emitting sector of SO2


and non-methane volatile


organic compounds and the main emitting sector of other air pollutants, including greenhouse gases.


Global increases in anthropogenic greenhouse gas emissions and climate impacts have occurred, even while mitigation activities have taken place in many parts of the world. Globally, economic and population growth continue to be the most important drivers of increases in CO2


emissions from fossil


fuel combustion. Atmospheric concentrations of long-lived greenhouse gases continue to increase, driven primarily by fossil fuel extraction and use for electricity generation, industry and transport, although they are also affected by land use, land-use change, agriculture and forestry (well established). The evidence of current global climate change is unequivocal (well established). Since 1880, the global average surface temperature has increased by between approximately 0.8 degrees Celsius and 1.2 degrees Celsius (very likely). Eight of the ten warmest years on record have occurred within the past decade (virtually certain). If greenhouse gas emissions persist, global average temperatures will continue to increase at the current rate, crossing the temperature target agreed as part of the Paris Agreement between 2030 and 2052 (very likely). The Paris Agreement committed countries to holding the increase in the global average temperature to well below 2 degrees Celsius above pre-industrial levels and pursuing efforts to limit the temperature increase to 1.5 degrees Celsius above pre-industrial levels, recognizing that doing so would significantly reduce the risks and impact of climate change. Current nationally determined contributions, presented in Paris in 2015, constitute only one third of the mitigation required to establish a least- cost pathway for staying well below 2 degrees Celsius (well established). {2.2, 2.7, 4.2.1, 5.2, 5.3.4} To maintain a good chance of remaining well below a 2 degrees Celsius temperature increase, emissions need to drop by between 40 and 70 per cent globally between 2010 and 2050, falling to net zero by 2070. {2.7.4}


Achieving the goals set out in the Paris Agreement requires transformational changes leading to deep reductions in greenhouse gas emissions and the balancing of emission sources and sinks (established but incomplete). In addition to emissions reductions for CO2,


the main anthropogenic greenhouse


gas, decreasing emissions of short-lived climate pollutants (also called forcers), specifically black carbon, methane, tropospheric ozone and hydrofluorocarbons, provide opportunities to limit warming in the short term and are a critical component of an integrated climate change mitigation and air-quality management programme. However, since long-lived greenhouse gases dominate climate forcing in the long term, decreasing emissions of short-lived climate pollutants in the short term needs to be combined with mitigation of long-term greenhouse gases. (well established). {4.2.1, 5.3.4} Non-CO2


emissions in pathways What is happening to our environment and how have we responded? 7


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