• China’s emissions glimpsing the peak


    China recently announced its intention to peak its carbon-dioxide emissions. How soon could the emissions peak and at what absolute value? Libo Wu explores.
  • The greening of the Southern Hemisphere


    The 2010-2011 La Niña weather event brought lush vegetation to vast semi-arid regions in the Southern Hemisphere and altered the delicate balance of the global carbon sinks. Owen Gaffney explores how La Niña might change in the future and what that might imply.

Earth system definitions

The term “Earth system" refers to Earth´s interacting physical, chemical, and biological processes.

The system consists of the land, oceans, atmosphere and poles. It includes the planet's natural cycles — the carbon, water, nitrogen, phosphorus, sulphur and other cycles — and deep Earth processes.
 
Life too is an integral part of the Earth system. Life affects the carbon, nitrogen, water, oxygen and many other cycles and processes.
 
The Earth system now includes human society, Our social and economic systems are now embedded within the Earth system. In many cases, the human systems are now the main drivers of change in the Earth system.

Global change

Global change refers to planetary-scale changes in the Earth system.
 
More completely, the term “global change" encompasses: planetary scale changes to atmospheric circulation, ocean circulation, climate, the carbon cycle, the nitrogen cycle, the water cycle and other cycles, sea-ice changes, sea-level changes, food webs, biological diversity, pollution, health, fish stocks, and more.
 
Civilization is now a large driver of global change so the term includes population, the economy, resource use, energy, development, transport, communication, land use and land cover, urbanization, globalization.

Global change and climate

Climate refers to the long-term average of the aggregation of all components of weather — precipitation, temperature and cloudiness, for example. The climate system includes processes involving ocean, land and sea ice in addition to the atmosphere.

The Earth system encompasses the climate system. Many changes in Earth system functioning directly involve changes in climate. However, the Earth system includes other components and processes, biophysical and human, that are important for its functioning.

Some Earth system changes, natural or driven by humans, can have significant consequences without involving changes in climate. Global change should  not be confused with climate change; it is significantly more. indeed, climate change is part of this much larger challenge.

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