AR5(IPCC第五次评估报告)

The fraction of SWR reflected back to space
30% reflected by the Earth’s surface
20% is absorbed in the atmosphere
Definition -- Climate System
Main drivers of climate change
clouds, which themselves emit LWR into all directions.
Definition -- Climate System
Main drivers of climate change
Natural fluctuations in solar output (solar cycles) can cause changes in the energy balance (through fluctuations in the amount of incoming SWR)
• Climate change can lead to other effects on the Earth's physical system that are also indicators of climate change. Such as changes in sea level
Sea Level
• There are many indicators of climate change. These include physical responses such as changes in the following:
➢ surface temperature, ➢ atmospheric water vapour, ➢ precipitation, ➢ severe events, ➢ glaciers, ➢ ocean and land ice, ➢ and sea level.
LWR emitted from the Earth’s surface is largely absorbed by certain atmospheric constituents — water vapour, carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O) and other greenhouse gases (GHGs);
Human activity changes the emissions of gases and aerosols, which are involved in atmospheric chemical reactions, resulting in modified O3 and aerosol amounts .
Anthropogenic changes in GHGs
Surface albedo is changed by changes in vegetation or land surface properties, snow or ice cover and ocean colour
Indicators of Climate Change
• Global mean sea level is an important indicator of climate change. The previous assessments have all shown that observations indicate that the globally averaged sea level is rising.
Definition -- Climate System
Main drivers of climate change
Cloud interactions with SWR and LWR are large, small changes in the properties of clouds have important implications for the radiative budget
气候变化与海平面上升
Profile
• Climate • Climate System • Indicator of Climate Change • Sea Level
Definition -- Climate
• Narபைடு நூலகம்ow sense：
– average weather: statistical description in terms of the mean and variability of relevant quantities over a period of time ranging from months to thousands or millions of years temperature precipitation wind ...
Definition -- Climate System
• The Earth's climate system is powered by solar radiation
Main drivers of climate change
about half of SWR is absorbed by the Earth’s surface
• Wider sense
– associated statistics, often combining parameters to describe phenomena
Definition -- Climate Change
• A change in the state of the climate that can be identified by changes in the mean and/or the variability of its properties, and that persists for an extended period, typically decades or longer.