Atmospheric science concerns itself with investigating the physical, chemical and radiative properties of the Earth’s atmosphere. Polar atmospheric science received a great deal of attention in the late 20th century with the 1985 discovery of the Antarctic “Ozone Hole”; a discovery that led to the Montreal Protocol and a comprehensive global ban of chlorofluorocarbons. While the monitoring of CFC’s and studies of polar stratospheric clouds continues, polar atmospheric science has received renewed attention during the IPY because of its important role in global climate.
The atmosphere over Antarctica serves as a laboratory for investigating the remote background atmosphere. Since it is far from anthropogenic pollution sources, short-lived species (e.g. aerosols, VOC’s) are nearly absent. However, the presence of long-lived trace gases (e.g. CO2) is used to study the rate of global redistribution of man-made pollution. We find that the Arctic atmosphere is much different than its antipode. Each spring the Arctic atmosphere is affected by “Arctic Haze”. This winter/spring reduction in visibility within the polar vortex has been observed since at least the 1950’s and is directly attributed to anthropogenic air pollution in the Northern Hemisphere.
The buildup of atmospheric pollution in the Arctic is of particular concern for two reasons. First, atmospheric aerosols scatter and absorb incoming/outgoing solar radiation directly affecting the radiation budget of the Arctic environment. Anthropogenic aerosols typically contain light-absorbing black carbon which can lead to direct heating of the Arctic atmosphere; heating which is in addition to the gradual rise of global temperature due to GHG’s. Second, aerosols serve as cloud and ice condensation nuclei making them a key component of the hydrological cycle. The light-absorbing properties of the aerosol continue once they are deposited with precipitation. This reduction in snow/ice albedo potentially affects the terrestrial hydrological cycle of the Arctic by accelerating the melting of permanent snow and ice. The composition of meltwaters is also affected since trace-gases and aerosols can deposit inorganic salts (e.g. H2SO4, HNO3, NH4+), trace metals (e.g Hg0, Cd), and volatile organic compounds (e.g. benzene, MTBE) which are not ordinarily found in the Polar Regions.
As we so often find in Polar Science, the study of the polar atmospheres is more difficult than at mid-latitudes. Satellites retrievals over the poles are complicated by bright surface targets (i.e. snow, ice) as well as seasonal or persistent cloud cover. Also, there is a dearth of surface-based and vertical column measurements with which to constrain global climate models. Many of these and other issues related to Polar Atmospheric Science were investigated during IPY. And in the years to come, answers to some questions may be found within the IPY data. However, the sparse nature of the observations, their short duration, and the rapidly changing environment of the Polar Regions will ensure that study of the Earth’s Polar Atmospheres will continue for years to come.
What is the difference between Climate and a Climate System?
Climate - The long-term average of conditions in the atmosphere, ocean, and ice sheets and sea ice described by statistics, such as means and extremes.
Climate System - The matter, energy, and processes involved in interactions among Earth’s atmosphere, hydrosphere, cryosphere, lithosphere, biosphere, and Earth-Sun interactions.
What is the difference between Climate Change and Global Warming?
Climate Change - A significant and persistent change in the mean state of the climate or its variability. Climate change occurs in response to changes in some aspect of Earth’s environment: these include regular changes in Earth’s orbit about the sun, re-arrangement of continents through plate tectonic motions, or anthropogenic modification of the atmosphere.
Global Warming - The observed increase in average temperature near the Earth’s surface and in the lowest layer of the atmosphere. In common usage, “global warming” often refers to the warming that has occurred as a result of increased emissions of greenhouse gases from human activities. Global warming is a type of climate change; it can also lead to other changes in climate conditions, such as changes in precipitation patterns.
CLIMATE LITERACY: The Essential Principles of Climate Science
- The Sun is the primary source of energy for Earth’s climate.
- Climate is regulated by complex interactions among components of the Earth system.
- Life on Earth depends on, is shaped by, and affects climate.
- Climate varies over space and time through both natural and man -made processes.
- Our understanding of the climate system is improved through observations, theoretical studies, and modeling.
- Human activities are impacting the system.
- Climate change will have consequences for the Earth system and human lives.