Earth and its environment are driven by increases in population and industrial development, which change greenhouse gas and particulate compositions in the atmosphere, as well as land cover, as well as by naturally occurring variations in solar energy which propagates to Earth as both particulate and electromagnetic energy, and volcanic emissions. The Intergovernmental Panel on Climate Change has stated in its Fourth Assessment Report (Synthesis Report, Summary for Policymakers) that "Most of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic GHG concentrations."
Quantitatively determining the relative contributions of human-induced and naturally-occurring climate forcing is an important scientific challenge with significant societal and political interest. The current view as summarized by the IPCC is that "The net effect due to human activities since the pre-industrial era is one of warming (+1.6 [+0.6 to +2.4] W/m2). In comparison, changes in solar irradiance are estimated to have caused a small warming effect (+0.12 [+0.06 to +0.30] W/m2)." The overall warming picture appears more complex, in some small part, due to shorter-term upper atmosphere interactions with Earth's solar-forced electromagnetic space environment. Given the ability of the ever-changing solar output and the dynamic response to it to alter Earth's global environment, the global atmosphere and the myriad of sensitive technical systems that facilitate the activities of society around the world, it is important to quantify these interactions and to assess how to best include them in analyses and projections of future global change.
This workshop will convene scientists who study the solar-terrestrial environment and those who study global change. The purpose is to assess our level of understanding of the system by: identifying recent advances connecting solar changes to changes in Earth's global environment in the context of changes in greenhouse gases, aerosols, and land cover; identifying gaps in our knowledge; and identifying interdisciplinary research topics to improve predictions of solar-terrestrial influences on Earth's global environment and its people in the context of the full range of global change forcings and feedbacks. In short -- What do we know? What don't we know? What are the top four research projects that can improve our present knowledge?
A particular emphasis will be the identification and discussion of the consequences of decadal to multi-decadal variations through which the solar-terrestrial environment affect global change, and conversely. Examples include: Earth's slowly weakening magnetic shield influencing solar and cosmic ray energy reaching the atmosphere and the biosphere; the weakening magnetic field in sunspots and solar wind; multi-solar-cycle scale variations in the Sun's radiative output; ionospheric elevation caused by cooling and contraction of the Earth's upper atmosphere; and many more. Particular emphasis will be given to the representation of these processes in climate models, the quantitative testing of process models, and the scientific efforts that can contribute now and in the future to the verification of these process models.
An Interdisciplinary Focus
The interdisciplinary nature of the attendees will assure that the elements of the Sun-Earth system will be discussed in a cross-disciplinary way, and that the overlap into societal impact will be a constant consideration. Workshop participants will include experts in heliophysics, chemistry, climate modeling, space weather, and biology/ecosystems, among others. Workshop products include a journal review article on the state of knowledge and research outlook and a more popular article for policy makers and the public on the significance of understanding the vulnerabilities related to changes in the entire Sun-Earth system, and their relative contributions to global change. A joint session at the 2010 Fall AGU could follow if deemed beneficial.
Workshop Topic (s):
- Land-Use/Land-Cover Change