Final answer:
The trend for Earth's temperatures over the past several decades has been increasing. The rise in greenhouse gases from fossil-fuel burning since the Industrial Revolution is the primary cause. Scientists use data from various sources to predict future temperature changes. The correct option is (c).
Step-by-step explanation:
Over the past several decades, the overall trend for earth's temperatures has been increasing. This trend is aligned with the observations made by scientists that the average annual temperature on Earth has been rising for the past 100 years, particularly since the Industrial Revolution due to a steady increase in fossil-fuel burning. These activities have led to higher concentrations of greenhouse gases in the atmosphere, which trap heat and cause temperatures to rise.
Global temperatures have been affected by various factors including volcanic eruptions, changes in the earth's orbit, and change in solar intensity. However, it is the increased emission of greenhouse gases that has been the dominant force behind the rise in temperatures, causing shifts in temperature and rainfall patterns. Scientists use various methods to predict changes in Earth's temperature, such as analyzing ice cores, tree rings, and measuring greenhouse gas levels in the atmosphere.
While there are natural variations in climate, the anthropogenic influence is clear. Increases in the global average air and ocean temperatures, the intensity of precipitation events, and a shift in the patterns of temperature and rainfall globally have been documented.