Final answer:
Global Net Primary Production (NPP) measures the organic material in an ecosystem, and predicting its future changes involves analyzing the impact of temperature increase on forest ecosystems.
Step-by-step explanation:
The global Net Primary Production (NPP) is an important measure in ecology that represents the amount of organic material available for other organisms in an ecosystem. It is calculated by subtracting the carbon dioxide respired by plants (R) from the total amount of carbon fixed by photosynthesis (P).
When making predictions about changes in NPP, various factors such as temperature increases can have significant effects. For instance, with a predicted temperature increase of 3-5°C by the year 2100, one would need to evaluate data to predict the impact on the NPP in a deciduous forest ecosystem, taking into consideration the current average summer temperature and the expected alterations due to climate change.