Climate change, climate modes, and climate impacts

“….large-scale seasonal indices…are remarkably good predictiors of ecological variation…” (Hallet et al 2004)

Modal variability Ecological correlations with modes and IAV are known from: Terrestrial Marine Physiological Ecosystem Community Population

Climate and Ecosystems The challenge facing ecologists is to identify the appropriate climatic variables to use (Hallet et al 2004) Moist Frozen Dry

Ecosystems respond to syndromes of climate: energy balance, water balance and not single variables Growing season length Note the reversed signs: warm springs mean dry summers

Modes and IAV 1.Periodic 2.Spatially coherent 3.Correlated changes in physics 4.Climate changes may be “projected” into modal patterns and frequencies

Modes and IAV 1.Produce spatially correlated responses 2.Modify multiple governing variables simultaneously 3.Affect populations by spatial correlation, producing long- term effects by e.g. affecting entire age cohorts

Interannual variability carbon fluxes Bacastow and Keeling Whoa

Clues to complex causation Most of the Indonesian wildfire burned in landscapes like those to the right Was this ENSO or land use change Or is that the wrong question?

Climate affects ecosystems and ecosystem services It always has, but the nature and severity of the responses, the vulnerability, of human-dominated systems is different from that of more natural systems