Query: “The IPCC reports also don’t fully account for the albedo effect (less ice means less reflected and more absorbed sunlight, hence more warming); more cloud cover (which traps heat); or the dieback of forests and other flora (which extract carbon from the atmosphere).

Relevant passages:
Tipping points in the climate system <=SEP=> A tipping point in the climate system is a threshold that, when exceeded, can lead to large changes in the state of the system. Potential tipping points have been identified in the physical climate system, in impacted ecosystems, and sometimes in both. For instance, feedback from the global carbon cycle is a driver for the transition between glacial and interglacial periods, with orbital forcing providing the initial trigger. Earth's geologic temperature record includes many more examples of geologically rapid transitions between different climate states.Climate tipping points are of particular interest in reference to concerns about global warming in the modern era. Possible tipping point behaviour has been identified for the global mean surface temperature by studying self-reinforcing feedbacks and the past behavior of Earth's climate system. Self-reinforcing feedbacks in the carbon cycle and planetary reflectivity could trigger a cascading set of tipping points that lead the world into a hothouse climate state.Large-scale components of the Earth system that may pass a tipping point have been referred to as tipping elements. Tipping elements are found in the Greenland and Antarctic ice sheets, possibly causing tens of meters of sea level rise. These tipping points are not always abrupt. For example, at some level of temperature rise the melt of a large part of the Greenland ice sheet and/or West Antarctic Ice Sheet will become inevitable; but the ice sheet itself may persist for many centuries. Some tipping elements, like the collapse of ecosystems, are irreversible.

Albedo <=SEP=> Albedo ( -LSB- ælˈbiːdoʊ -RSB- ) is a measure for reflectance or optical brightness ( Latin albedo , Arabic albayad , `` whiteness '' ) . It is dimensionless and measured on a scale from zero ( corresponding to a black body that absorbs all incident radiation ) to one ( corresponding to a white body that reflects all incident radiation ) .   Surface albedo is defined as the ratio of radiation reflected to the radiation incident on a surface . The proportion reflected is not only determined by properties of the surface itself , but also by the spectral and angular distribution of solar radiation reaching the Earth 's surface . These factors vary with atmospheric composition , geographic location and time ( see Position of the Sun ) . While bi-hemispherical reflectance is calculated for a single angle of incidence ( i.e. , for a given position of the sun ) , albedo is the directional integration of reflectance over all solar angles in a given period . The temporal resolution may range from seconds ( as obtained from flux measurements ) to daily , seasonal or annual averages .   Unless given for a specific wavelength ( spectral albedo ) , albedo refers to the entire spectrum of solar radiation . Due to measurement constraints , it is often given for the spectrum in which most solar energy reaches the surface ( approximately between 0.3 and 3 μm ) . This spectrum includes visible light ( 0.39-0 .7 μm ) , which explains why surfaces with a low albedo appear dark ( e.g. , trees absorb most radiation ) , whereas surfaces with a high albedo appear bright ( e.g. , snow reflects most radiation ) .   Albedo is an important concept in climatology , astronomy , and environmental management ( e.g. , as part of the Leadership in Energy and Environmental Design ( LEED ) program for sustainable rating of buildings ) . The average albedo of the Earth at the top of the atmosphere , its planetary albedo , is 30 to 35 % because of cloud cover , but widely varies locally across the surface because of different geological and environmental features .   The term albedo was introduced into optics by Johann Heinrich Lambert in his 1760 work Photometria .

Global warming <=SEP=> Global warming , also referred to as climate change , is the observed century-scale rise in the average temperature of the Earth 's climate system and its related effects . Multiple lines of scientific evidence show that the climate system is warming . Many of the observed changes since the 1950s are unprecedented in the instrumental temperature record which extends back to the mid 19th century , and in paleoclimate proxy records over thousands of years .   In 2013 , the Intergovernmental Panel on Climate Change ( IPCC ) Fifth Assessment Report concluded that `` It is extremely likely that human influence has been the dominant cause of the observed warming since the mid-20th century . '' The largest human influence has been emission of greenhouse gases such as carbon dioxide , methane and nitrous oxide . Climate model projections summarized in the report indicated that during the 21st century the global surface temperature is likely to rise a further 0.3 to for their lowest emissions scenario and 2.6 to for the highest emissions scenario . These findings have been recognized by the national science academies of the major industrialized nations and are not disputed by any scientific body of national or international standing .   Future climate change and associated impacts will differ from region to region around the globe . Anticipated effects include warming global temperature , rising sea levels , changing precipitation , and expansion of deserts in the subtropics . Warming is expected to be greater over land than over the oceans and greatest in the Arctic , with the continuing retreat of glaciers , permafrost and sea ice . Other likely changes include more frequent extreme weather events including heat waves , droughts , heavy rainfall with floods and heavy snowfall ; ocean acidification ; and species extinctions due to shifting temperature regimes . Effects significant to humans include the threat to food security from decreasing crop yields and the abandonment of populated areas due to rising sea levels . Because the climate system has a large `` inertia '' and greenhouse gases will stay in the atmosphere for a long time , many of these effects will not only exist for decades or centuries , but will persist for tens of thousands of years .   Possible societal responses to global warming include mitigation by emissions reduction , adaptation to its effects , building systems resilient to its effects , and possible future climate engineering . Most countries are parties to the United Nations Framework Convention on Climate Change ( UNFCCC ) ,  whose ultimate objective is to prevent dangerous anthropogenic climate change . Parties to the UNFCCC have agreed that deep cuts in emissions are required and that global warming should be limited to well below 2.0 C-change relative to pre-industrial levels , with efforts made to limit warming to 1.5 C-change .   Public reactions to global warming and concern about its effects are also increasing . A global 2015 Pew Research Center report showed a median of 54 % consider it `` a very serious problem '' . There are significant regional differences , with Americans and Chinese ( whose economies are responsible for the greatest annual CO2 emissions ) among the least concerned .