Rcp2.6 Paris Agreement

Chart 2.1 | (a) Time series of global annual variation in average surface temperature for the period 1900-2300 (compared to 1986-2005) from concentration experiments in the Phase 5 coupled model comparison project (CMIP5). Projections are indicated for the multimode average (interspersed lines) and the range of 5% to 95% on the distribution of each model (nuance). The grey lines and shades represent the historical CMIP5 simulations. The discontinuities to 2100 are due to a different number of models that run the extension and go beyond the 21st century and have no physical significance. b) as (a) but for the period 2006-2100 (compared to the period 1986-2005). c) Change in the expansion of sea ice in the Northern Hemisphere in September (average of 5 years). The dotted line represents almost ice-free conditions (i.e., when the extent of the sea ice is less than 106 km2 at least five consecutive years in September). (d) changes in global average sea level. (e) the change in the pH of the sea surface. For all panels, the amendments relate to the period 1986-2005; The time series of projections and a measurement are presented for the scenarios RCP2.6 (blue) and RCP8.5 (red). The number of CMIP5 models used to calculate the average value for multiple models is indicated.

For all CPR scenarios, the average uncertainties and uncertainties associated with them are indicated in the form of coloured vertical bars on the right side of the panels (b) to (e) for all CPR scenarios. With respect to line ice expansion (c), the projected average and uncertainty (maximum minimum range) are indicated only for the sub-quantity of models most likely to replicate the average climatological state and the 1979-2012 trend in the Arctic sea ice. For sea level (d), based on current understanding (based on observations, physical comprehension and modeling), only the collapse of marine areas of the Antarctic ice sheet, when initiated, could result in a significant increase in average sea level in the 21st century above the likely range. However, there is an average confidence that this additional contribution in the 21st century would not exceed a sea level rise of several tenths of a metre. WGI SPM.7 Figure SPM.9, Figure 12.5, 6.4.4, 12.4.1, 13.4.4, 13.5.1 Climate change in the 21st century is expected to reduce renewable surface and underground resources in most dry subtropical regions (solid evidence, high match), exacerbating competition for water between sectors (limited evidence, average consent).