Final answer:
The melting of sea ice is primarily caused by rising global temperatures, not baking soda. It occurs due to heat energy being trapped in the Earth's atmosphere, resulting in increased temperatures and ice melting in polar regions.
Step-by-step explanation:
The melting of sea ice is primarily caused by rising global temperatures, which can be attributed to human activities and the increase of greenhouse gases in the atmosphere. Baking soda, scientifically known as sodium bicarbonate (NaHCO3), is not responsible for the melting of sea ice. The phenomenon occurs when heat energy from the sun is trapped in the Earth's atmosphere, leading to increased temperatures and resulting in the melting of ice in polar regions.