What are the key regional drivers of future climate change?

Globally, greenhouse gas forcing is the key driver in policy-relevent climate change (ie. over the next 20, 50, 100 years). Regionally -at the scales people live, ecosystems function, water is obtained and crops grown, other forcings can dominate. Land cover change, urbanization, industrial aerosols etc can all have regional fingerprints that while globally small are locally dominant. Other modes of variability, ocean-atmopshere coupling, land-atmopshere coupling, orographic effects etc all can be locally dominant drivers even if they are lost in any global measure of climate change. A research program to understand drivers of climate change at the scales that people live is hugely challenging at a scientific level, technical level for the modelling and in terms of research at the interface of risk and vulnerability.

How can local and regional environmental changes be scaled accurately and effectively to enhance the assessment of global changes, and vice-versa? How can we enhance the applicability of global predictions of biodiversity loss, water scarcity, climate change etc. to local and regional decision-making?

Environmental change occurs at varying temporal and spatial scales. Therefore it is imperative we understand how to utilize existing models and scientific understanding to create realistic predictions of biophysical thresholds and environmental consequences that governments and communities can utilize and comprehend. Furthermore, we need to understand how to relate the mitigation, adaptation, and conservation policies of a given locality to the Earth system. Knowledge of how to effectively scale human decisions and environmental change will significantly aid our ability in generating tangible action towards cooperative solutions.

What are the regional expressions of climate change?

Over the last decades and years, the question of climate change attribution has been resolved scientifically and we have made good progress in constraining the magnitude of greenhouse warming at a global scale. In contrast, the regional expression of climate change is still poorly understood, hence providing a vague physical basis for foresighted political decisions and socioeconomic planning.

Gaps to fill in our knowledge on regional climate relate to regional trends and magnitudes of monsoon precipitation, drought in subtropical regions of both hemispheres, Arctic warming (including melt of sea ice and Greenland ice), prevalent climate modes and seasonality in mid-latitude regions, etc.

Focused research over the next decade should be able to constrain many of the uncertainties about the regionally relevant aspects of climate change. Such research needs to address regional climate dynamics across past and present timescales, based on targeted, high-resolution climate modeling and the generation and analysis of detailed paleo-climate reconstructions and climate-observation datasets. Without better-founded expectations about regional changes, any research on global change impacts and adaptation measures will be built on sand and remain speculative.

How best can we plan ESS experiments on regional scales that address issues of immediate concern to the local population and help long term planning at regional/global scales?

We have acquired a fairly broad understanding of how our earth systems, land-ocean-atmosphere-biosphere, function and interactions among them. Most of this information is a result of connecting the fragmented research on different aspects at different locations and extrapolating the same to global scales. Crucial to the existence of life on this planet are the interactions and functioning of the earth system compartments at regional levels. It is time that we plan regional experiments to answer questions, relevant to the existing society and changing ecosystems, of immediate interest with a strategy that will allow us forecast future scenarios.