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| "Was it Decision time in..." |
| Was it Decision time in Copenhagen? |
| Global Climate Change |
| Global Warming | |||
| Currently within 1¼C of highest Temp. in 125,000 years | |||
| forced versus unforced fluctuations | |||
| Radiatively active gases; | |||
| Carbon dioxide (CO2) | |||
| Methane (CH4) | |||
| Nitrous oxide (N2O) | |||
| Chlorofluorocarbons (CFCs) | |||
| H2O vapor | |||
| Attribution |
| Asks whether observed changes are consistent with | |
| expected responses to forcings | |
| inconsistent with alternative explanations | |
| Most of the observed increase in globally averaged temperatures since the mid-20th century is very likely (>90% certainty) due to the observed increase in anthropogenic greenhouse gas concentrations |
| Source: Thompson et al.
2008. ENSO = El Nino/ Southern Oscillation COWL= cold ocean, warm land |
| Source: Thompson et al., 2008. |
| Slide 7 |
| Observed Vs. modeled temperature rise since 1860 |
| Computer Model Comparison of Anthropogenic and Natural Forcing (red) vs. Only Natural Forcing (blue) |
| Understanding and Attributing Climate Change |
| 1000 Years of CO2 and Temperatures |
| Fig. 10.28 Global temperature trends, 1880-2003 |
| Slide 13 |
| Temperature trends |
| Temperature Anomalies |
| 10,000 Years of Greenhouse Gases |
| Slide 17 |
| WhatÕs in the pipeline and what could come |
| Warming will increase if GHG increase. If GHG were kept fixed at current levels, a committed 0.6¡C of further warming would be expected by 2100. More warming would accompany more emission. |
| Surface Temperature Projections |
| Changing winds,
temperatures and storm tracks |
| ¥ Anthropogenic forcing has likely contributed to circulation changes (storm tracks, winds and temperature patterns) | |
| Warmer, wetter winters in Norway; drier in Spain (and North Africa) |
| Slide 21 |
| Projections of Future Changes in Climate |