Vulnerability to climate change is determined by exposure to risks, sensitivity to impacts, and ability to adapt. Adaptation involves adjusting systems in response to actual or expected climate changes to moderate harm or exploit opportunities. There are two types of adaptation: autonomous reactive adaptation and anticipatory proactive adaptation. Estimating future agricultural responses to climate change involves using scenarios to explore possible adaptive measures, as scenarios do not necessarily describe what will actually occur. Biophysical impacts of climate change include changes in crop and livestock conditions, precipitation, water resources, pests, and soil quality. These can result in changes to crops grown, farming types, production, income, employment, GDP contribution, and export earnings.