Key Points for Policy and Decision Makers, and Tourism Operators

• Human influences on the climate are predominantly through a process known as radiative forcing, resulting in global climate change. The latter is often referred to as 'global warming' despite the changes being much more diverse and complex than a simple increase in the global mean temperature.

• The largest single contributor to radiative forcing is the increased atmospheric concentration of CO2 as a result of the burning of fossil fuels. The tourism sector is a major user of such fuels, for transport as well as heating, cooling and lighting. Overall, tourism contributes some 5% of the global emissions of gases that result in radiative forcing and hence climate change.

• The tourism sector is already experiencing disruptive changes consistent with many of the anticipated consequences of climate change, including abnormally high air and ocean temperatures and sea levels, and increased destructiveness of tropical cyclones.

• Ozone depletion and global warming are linked, but they result from very different processes, namely chemical destruction of ozone, a highly important atmospheric constituent, and increased atmospheric concentrations of GHG.

• The story lines underpinning climate projections combine futures that range between strong economic values and strong environmental values on the one hand and between increasing globalisation and increasing regionalism on the other.

• Because of the diversity and complexity of climate-determining processes, and despite the considerable and growing intricacy of global climate models, it is still not possible to simulate the full range of interactions between and within the components of the global climate system; the resulting uncertainties regarding future climates are exacerbated by knowledge gaps.

• Increases in temperature are projected to occur at high northern latitudes and over land, with relatively less warming over the southern oceans and the North Atlantic.