Klimatske promjene, paleoklimatologija Ivica Vilibić Institut za oceanografiju i ribarstvo, Split vilibic@izor.hr

Key concepts of the last lecture: Općenito o razini mora Plima i oseka Olujni uspori Sezonske oscilacije razine mora Višegodišnje promjene razine mora

Današnje predavanje: Što su klimatske promjene Recentne klimatske promjene Paleoklimatologija Projekcije za budućnost Materijali preuzeti: Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, 2007 www.ipcc.ch

Klimatske promjene Klima kao meteorološki pojam je skup meteoroloških čimbenika i pojava koje u određenom vremenskom periodu čine prosječno stanje atmosfere nad nekim dijelom Zemljine površine. Klimatske promjene ili promjene klime označavaju dugotrajne i značajne promjene prosječnih klimatskih uvjeta na zemlji. Estimate of the Earth’s annual and global mean energy balance. Over the long term, the amount of incoming solar radiation absorbed by the Earth and atmosphere is balanced by the Earth and atmosphere releasing the same amount of outgoing longwave radiation.

Klimatske promjene Staklenički plinovi This figure shows the absorption bands in the Earth's atmosphere (middle panel) and the effect that this has on both solar radiation and upgoing thermal radiation (top panel). Individual absorption spectrum for major greenhouse gases are shown in the lower panel.

Klimatske promjene Staklenički plinovi Mauna Loa Recent CO2 concentrations and emissions.

Klimatske promjene Temperatura zraka (Top) Annual global mean observed temperatures (black dots) along with simple fits to the data. (Bottom) Patterns of linear global temperature trends from 1979 to 2005 estimated at the surface (left), and for the troposphere (right) from the surface to about 10 km altitude, from satellite records.

Klimatske promjene Oborine The most important spatial pattern (top) of the monthly Palmer Drought Severity Index (PDSI) for 1900 to 2002. The PDSI is a prominent index of drought and measures the cumulative deficit (relative to local mean conditions) in surface land moisture by incorporating previous precipitation and estimates of moisture drawn into the atmosphere (based on atmospheric temperatures) into a hydrological accounting system. Red and orange areas are drier than average and blue and green areas are wetter than average when the values shown in the lower plot are positive.

Klimatske promjene Ekstremi Observed trends (days per decade) for 1951 to 2003 in the frequency of extreme temperatures, defined based on 1961 to 1990 values

Klimatske promjene Led Anomaly time series (departure from the long-term mean) of polar surface air temperature (A, G), arctic and antarctic sea ice extent (B, F), Northern Hemisphere (NH) frozen ground extent (C), NH snow cover extent (D) and global glacier mass balance (E).

Klimatske promjene Temperatura mora Time series of global annual ocean heat content for the 0 to 700 m layer

Klimatske promjene Vodene mase Meridional sections of differences in salinity (psu) of the a) Atlantic Ocean for the period 1985 to 1999 minus 1955 to 1969 and b) Pacific Ocean for the World Ocean Circulation Experiment (WOCE) 150°W section (1991–1992) and historical data from 1968 plus or minus 7.5 years.

Klimatske promjene Otopljeni CO2 Changes in surface oceanic pCO2 (left; in μatm) and pH (right) from three time series stations

Klimatske promjene Razina mora Annual averages of the global mean sea level (mm). The red curve shows reconstructed sea level fields since 1870 (updated from Church and White, 2006); the blue curve shows coastal tide gauge measurements since 1950 (from Holgate and Woodworth, 2004) and the black curve is based on satellite altimetry (Leuliette et al., 2004)

Klimatske promjene Oceani Schematic of the observed changes in the ocean state, including ocean temperature, ocean salinity, sea level, sea ice and biogeochemical cycles. The legend identifies the direction of the changes in these variables.

Klimatske promjene Zadnjih tisuću godina Records of Northern Hemisphere temperature variation during the last 1.3 kyr.

Klimatske promjene Zadnjih 600 kyr Variations of deuterium (δD; black), a proxy for local temperature, and the atmospheric concentrations of the greenhouse gases CO2 (red), CH4 (blue), and nitrous oxide (N2O; green) derived from air trapped within ice cores from Antarctica and from recent atmospheric measurements. The shading indicates the last interglacial warm periods.

Klimatske promjene Zadnjih 600 kyr Milankovićevi ciklusi Past and future daily-average insolation at 65 N, on day of summer solstice. Blue dot is current condition, 2 ky A.D.

Klimatske promjene Zadnjih 5 Myr This figure shows the climate record of Lisiecki and Raymo (2005) constructed by combining measurements from 57 globally distributed deep sea sediment cores. The measured quantity is oxygen isotope fractionation ([[δ18O]]) in benthic foraminifera, which serves as a proxy for the total global mass of glacial ice sheets

Klimatske promjene Zadnjih 500 Myr Atmospheric CO2 and continental glaciation 400 Ma to present. Global compilation of deep-sea benthic foraminifera 18-O isotope records from 40 Deep Sea Drilling Program and Ocean Drilling Program sites. Detailed record of CO2 for the last 65 Myr.

Klimatski modeli Verifikacija Global mean near-surface temperatures over the 20th century from observations (black) and as obtained from 58 simulations produced by 14 different climate models driven by both natural and human-caused factors that influence climate (yellow). The mean of all these runs is also shown (thick red line).

Klimatske projekcije Temperatura zraka Multi-model mean of annual mean surface warming (surface air temperature change,°C) for the scenarios B1 (top), A1B (middle) and A2 (bottom), and three time periods, 2011 to 2030 (left), 2046 to 2065 (middle) and 2080 to 2099 (right).

Klimatske projekcije Oborine Multi-model mean changes in surface air temperature (°C, left), precipitation (mm day–1, middle) and sea level pressure (hPa, right) for boreal winter (DJF, top) and summer (JJA, bottom). Changes are given for the SRES A1B scenario, for the period 2080 to 2099 relative to 1980 to 1999.

Klimatske projekcije Hidrološki ciklus Multi-model mean changes in (a) precipitation (mm day–1), (b) soil moisture content (%), (c) runoff (mm day–1) and (d) evaporation (mm day–1).

Klimatske projekcije Led Multi-model mean sea ice concentration (%) for January to March (JFM) and June to September (JAS), in the Arctic (top) and Antarctic (bottom) for the periods (a) 1980 to 2000 and b) 2080 to 2100 for the SRES A1B scenario.

Meridional Overturning Circulation Klimatske projekcije Meridional Overturning Circulation Evolution of the Atlantic meridional overturning circulation (MOC) at 30°N in simulations with the suite of comprehensive coupled climate models. Of the model simulations consistent with the late-20th century observational estimates, no simulation shows an increase in the MOC during the 21st century; reductions range from indistinguishable within the simulated natural variability to over 50% relative to the 1960 to 1990 mean; and none of the models projects an abrupt transition to an off state of the MOC.

Oborinski i sušni ekstremi Klimatske projekcije Oborinski i sušni ekstremi (a) Globally averaged changes in precipitation intensity (defined as the annual total precipitation divided by the number of wet days), (b) Changes in spatial patterns of simulated precipitation intensity between two 20-year means (2080–2099 minus 1980–1999). (c) Globally averaged changes in dry days (defined as the annual maximum number of consecutive dry days). (d) Changes in spatial patterns of simulated dry days between two 20-year means (2080–2099 minus 1980–1999).

Temperaturni ekstremi Klimatske projekcije Temperaturni ekstremi Changes in extremes based on multi-model simulations from nine global coupled climate models.

Klimatske projekcije Razina mora - steric Local sea level change (m) due to ocean density and circulation change relative to the global average (i.e., positive values indicate greater local sea level change than global) during the 21st century, calculated as the difference between averages for 2080 to 2099 and 1980 to 1999, as an ensemble mean over 16 AOGCMs forced with the SRES A1B scenario.

Klimatske projekcije Razina mora Projections and uncertainties (5 to 95% ranges) of global average sea level rise and its components in 2090 to 2099 (relative to 1980 to 1999) for the six SRES marker scenarios. The projected sea level rise assumes that the part of the present-day ice sheet mass imbalance that is due to recent ice flow acceleration will persist unchanged.

Klimatske projekcije 1000 yrs (a) Atmospheric CO2, (b) global mean surface warming, (c) sea level rise from thermal expansion and (d) Atlantic meridional overturning circulation (MOC) calculated by eight EMICs for the SRES A1B scenario and stable radiative forcing after 2100, showing long-term commitment after stabilisation.

Klimatske projekcije 2000 yrs - led Evolution of Greenland surface elevation and ice sheet volume versus time in the experiment of Ridley et al. (2005) with the UKMO-HadCM3 AOGCM coupled to the Greenland Ice Sheet model of Huybrechts and De Wolde (1999) under a climate of constant quadrupled pre-industrial atmospheric CO2.