Executive Summary
xix
Natural systems related to snow, ice, and frozen ground (including permafrost) and hydrological systems are affected. The melting of ice sheets, glaciers, and ice caps has accelerated and sea levels have risen an average of 18 cm since the late 19th century. It is likely that the frequency of heavy precipitation events (or proportion of total rainfall from heavy falls) has increased over most areas. Extreme weather events have also changed in frequency and intensity since 1950. It is very likely that cold days, cold nights, and frosts have become less frequent over most land areas, while hot days and hot nights have become more frequent. It is likely that heat waves have become more frequent over most land areas. A modest change in the wind climate of some regions has been observed, with an increase in intense tropical cyclone activity in the North Atlantic since about 1970 (although there is less confidence in this statement). There is emerging evidence of variability in climate parameters. Besides trends, intra- and inter-annual climate variations are important for energy planning and operations. Europe and Central Asia is the only region with observed large inter-annual temperature variations; up to about 5°C in winter months (Table ES.2). Since a large portion of this region is covered in permafrost, the energy industry is vulnerable to these large temperature variations (for example, structural integrity of pipelines). Large deviations in near-surface wind speed have been observed over the oceans and, typically, during the colder season. Offshore operations in the Gulf of Mexico (particularly in the winter season) and areas in northwest Africa are exposed. Table ES.2. Summary Table of “Hotspots” Africa
2-meter T
Sizeable projected changes in variability
East Asia & Pacific
Europe & Central Asia
Large errors in Large observed observed seasonal variability; sizeable mean projected changes in variability
10-meter wind
Solar radiation
Large errors in observed annual mean; sizeable projected changes in high-end extremes
Sea level
Large observed changes
Middle East & North Africa
Large errors in observed seasonal mean; sizeable projected changes in variability
South Asia Large errors in observed seasonal mean
Large observed variability over ocean
Large observed variability over NW Africa
Large errors in observed annual mean
Sizeable projected changes in highend extremes
Large errors in observed annual mean; sizeable projected changes in high-end extremes Large observed changes
Risk of degradation and reduction
Permafrost
Sea ice
Latin America & Caribbean
Reported acceleration of melting of Greenland and Antarctic ice sheets
Source: Generated by authors. Note: Hotspots listed were identified in Chapter 2, sections “Climatic Impacts on Energy Services” and “Recent Observed Climate Change,” and hence are not comprehensive across all variables/statistics combinations. “Observed” refers to either direct observations or to outputs from re-analyses.