Answer
(a) It is a valid criticism. Melting ice will not increase the ocean levels as they are already part of the ocean. Infact the density of water is higher than ice. So ice from the ocean melting should, in fact, decrease the ocean level.
(b) Scientists are worried about ice melting caused by global warming that increases the sea level. Ice present on the continents which are already not part of the ocean would definitely increase the ocean levels. Ice mountains where ice is accumulated vertically would displace water from the ocean causing a rise in the ocean level.
Work Step by Step
(a) It is a valid criticism. Melting ice will not increase the ocean levels as they are already part of the ocean. Intact the density of water is higher than ice. So ice from the ocean melting should, in fact, decrease the ocean level.
(b) Scientists are worried about ice melting caused by global warming that increases the sea level. Ice present on the continents which is already not part of the ocean would definitely increase the ocean levels. Ice mountains where ice is accumulated vertically would displace water from the ocean causing a rise in the ocean level.
