Final answer:
Natural forces cannot explain the current rapid increase in global temperatures, which is largely due to the human-induced release of greenhouse gases from the burning of fossil fuels since the Industrial Revolution. This has led to an enhanced greenhouse effect, causing the observed warming trend.
Step-by-step explanation:
The current rapid increase in global temperatures cannot be attributed to natural forces such as volcanic eruptions, changes in solar intensity, or variations in ocean currents. Natural climate drivers do not account for the observed quick and consistent warming trend, especially after the Industrial Revolution. It is the human activity, predominately the burning of fossil fuels, which releases greenhouse gases like CO₂, that explains most of the warming.
Historical climate changes, including those during the Medieval Climate Anomaly or the Little Ice Age, can be understood within the context of natural variability. However, the recent changes, particularly since the mid-20th century, are far too rapid to be explained by these natural factors. Instead, human activities have altered the carbon cycle, intensifying the greenhouse effect and resulting in a significant and ongoing rise in global temperatures.
Greenhouse gases are known to increase air temperatures by absorbing infrared radiation. The significant rise in CO₂ and other greenhouse gas concentrations since the 1750s, largely from burning coal, oil, and deforestation, has led to an enhanced greenhouse effect and global warming. Future predictions based on climate models suggest an increase in the range of 1.8°-6.4° C in average global temperatures by the end of this century, depending on human actions to mitigate emissions.