Ecological systems have many interacting non-linear processes and are thus subject to abrupt changes and threshold effects arising from relatively small changes in driving variables, such as climate. For example:

• Temperature increase beyond a threshold, which varies by crop and variety, can affect key development stages of some crops and result in severe losses in crop yields. Examples of key development stages and their critical thresholds include spikelet sterility in rice (e.g., temperatures greater than 35°C for more than 1 hour during the flowering and pollination process greatly reduce flower formation and eventually grain production), loss of pollen viability in maize (>35°C), reversal of cold-hardening in wheat (>30°C for more than 8 hours), and reduced formation of tubers and tuber bulking in potatoes (>20°C). Yield losses in these crops can be severe if temperatures exceed critical limits for even short periods.
• Mangroves occupy a transition zone between sea and land that is set by a balance between the erosional processes from the sea and siltation processes from land. The erosional processes from the sea might be expected to increase with sea-level rise, and the siltation processes through climate change and other human activities (e.g., coastal development). Thus, the impact on the mangrove forests will be determined by the balance between these two processes, which will determine whether mangrove systems migrate landward or seaward.