Tracking Climate Change From Space

For centuries, rural communities in the high plateaus of the Andes have utilized water from melting glaciers that typify this amazing mountain range. But the retreat of these glaciers is forcing the communities to reconsider their livelihoods and ways to adapt. From a wider perspective, the melting of glaciers is an iconic warning to the larger cities in the Andes that rely on glaciers for potable water. Unfortunately for these communities, the source of this particular problem and its potential solution lie far away from their arc of influence due to the fact that local actions contribute very little to remedy this problem.

As noted in 2003 and 2007 by the Intergovernmental Panel on Climate Change (IPCC) the melting of glaciers in the Andes, the Himalayas, and the Alps is a consequence of global warming, a process induced by humans, and directly related to industrialization that has fuelled this century, particularly in terms of demand for energy from fossil fuels. The emissions of greenhouse gases such as carbon dioxide (CO2), nitrous oxide (N2O), methane (CH4), and the emission of aerosols have a direct influence on the radiative forcing (the difference between incoming and outgoing radiation energy) in the atmosphere, leading to global warming. Such global warming manifests itself through higher temperatures in the oceans and the atmosphere. In the case of oceans, heat absorption is the main factor leading to the increase in their levels. In the case of glaciers and polar caps, it leads to melting of ice. As expected, the melting of glaciers and ice in continental land masses in Antarctica and Greenland also contributes to the increase in sea level.

Governments recognized the need to address this problem at the global level, and established the IPCC to provide the scientific basis on which to characterize the scale and depth of the problem, and the United Nations Framework Convention on Climate Change (UNFCCC) as the mechanism to facilitate the political discussion on this issue at the international level. Organizations within the United Nations also play other relevant roles. For example, the World Meteorological Organization (WMO) has long supported the establishment and operation of national meteorological departments or offices which generate the data that are required to monitor the Essential Climate Variables (ECVs) such as air and water temperatures, sea ice, water vapour and salinity, etc. In addition, WMO heads the Global Climate Observing System (GCOS) which tracks these essential climate variables. Furthermore, national agencies and regional organizations around the world also contribute to monitor more variables such as ocean levels, the ozone layer and the chemical processes which affect it, and the role of forest fires as sources of some of these greenhouse gases, as a way to contribute to understanding the interactions between the oceans, land, and the atmosphere. For example, information gathered through satellites is ideally suited to track changes in the amount of ice stored in polar caps and glaciers. The capacity of satellites to provide standardized global coverage of all glaciers and ice caps on a permanent basis permits scientists to measure changes in a uniform and periodic fashion. The use of satellite instruments is ideal since harsh climatic conditions make it difficult to have a permanent human presence in all these areas yearlong. In addition, at the polar caps, it would be nearly impossible to measure in a periodic fashion and with sufficient accuracy the extension of ice caps and their dynamics, as there are no landmarks on which to set benchmarks to conduct the required geospatial measurements.

Considering the critical nature of climate change in recent years, space agencies have begun to establish space programmes dedicated to monitor and to track climate change. Dedicated satellites from a variety of space agencies now provide data related to atmospheric chemistry and its dynamics, changes in vegetation cover and the oceans. All this data contributes to a more precise estimation of climate change required by decision makers in Governments who demand such information to make commitments of various kinds along the lines of mitigation and adaptation contemplated in the Kyoto Protocol. Other space applications including assessing the impact of global warming on wetlands that host a variety of ecosystems and species; in the perennially frozen ground (permafrost); and in the oceans targeting plankton, marine ecosystems, and bio-chemical interactions at the surface of the oceans which are influenced by air and sea interactions.

In addition, satellites are being used to acquire the necessary data to track cloud formation and dissipation and convections processes between the troposphere and the stratosphere. The role of clouds on the radiative processes and in the hydrological cycle is essentially not well understood, and therefore, satellite data will allow IPCC to refine models and reduce uncertainties.

Satellites are also finding uses in the assessment of vulnerability to climate change. Space observations are ideal to complement ground-based measurements with the most up-to-date information on types of land-use and changes in land-use practices arising as a consequence of population growth, urban migration, conflicts and poverty. For example, vulnerability of coastal cities will be essential to identify adaptation measures. Assessing the vulnerability of crops in low-lying flood plains in coastal areas can also benefit from space-based information. In the context of risk assessment, space-based tools offer an ideal platform to assess the exposure of vulnerable elements not only to climate change, but also with respect to other hazards.

In the context of the United Nations, the Committee on the Peaceful Uses of Outer Space (COPUOS) is the forum where global agreements are reached, among others, on space debris, policies on the use of specific types of orbits, and more recently, global navigation systems and space legislation. In 1999, during the international conference, UNISPACE III, Member States recognized the contribution of space science and space applications to the well-being of humanity and sustainable development in areas such as disaster management, meteorological forecasting for climate modeling, satellite navigation, and communications.

The issue of climate change has been addressed within COPUOS recently in a dedicated symposium organized during the forty-sixth session of its Scientific and Technical Sub-Committee, and more recently during the fifty-second session, which took place in June 2009 in Vienna. Supporting COPUOS in its role as a Secretariat to facilitate the political dialogue among Member States, the United Nations Office for Outer Space Affairs (UNOOSA) has been doing a variety of work in recent decades to promote the use of space-based information. UNOOSA recently established UN-SPIDER -- Platform for Space-based Information for Disaster Management and Emergency Response. In addition, in recent years, the Space Applications Section and the Committee Services and Research Section of UNOOSA have been conducting a series of conferences and workshops targeting climate change in the context of mountains, sustainable development, agriculture and food security, and on the legal implications of space applications for climate change.

The vision of UNOOSA in the context of climate change is to promote the acquisition and subsequent use of data gathered through satellites to contribute to the understanding and modeling of climate change as a means to identify adaptation and mitigation measures, and as a means to track their impact in the long term. Such a vision may indeed pave the wave for communities in the Andes, as well as communities around the world, to make use of space-based information and become aware of the global extent of this problem, and for decision makers to grasp the full dimension of the problem in order to seal the deal in Copenhagen.

The views expressed in this article may not necessarily reflect the views of UNOOSA.

References IPCC (2001): Third Assessment Report. Climate Change 2001. 
http://www.ipcc.ch/publications_and_data/publications_and_data_reports.h...
IPCC (2007): Fourth Assessment Report. Climate Change 2007. 
http://www.ipcc.ch/publications_and_data/publications_and_data_reports.h...
OOSA (2009): Conference Room Paper No. 6. Ref. A/AC.105/2009/CRP.6.