What effect does the greenhouse effect currently have on Earth?

The greenhouse effect is a crucial natural process that allows the Earth to maintain a temperature conducive to life. It occurs when certain gases in the Earth's atmosphere trap heat, preventing it from escaping back into space. This process is essential for sustaining life, as it keeps the planet warm enough for liquid water to exist.

The fact that the greenhouse effect currently raises the Earth's average temperature by about 33 degrees Celsius (around 59 degrees Fahrenheit) indicates that the overall impact is significant and well above negligible levels. Thus, understanding the temperature increase due to natural greenhouse gases is critical. The correct answer falls outside of the negligible range indicated by less than 10 Kelvins.

In summary, while the greenhouse effect is necessary for maintaining habitable temperatures on Earth, the overall increase it provides is much more substantial than the minimal temperature shifts mentioned in the choices. This places the actual impact well into the "drastic" or "moderate" categories, rather than the negligible one proposed.