The climax of the film is quite clearly when the comet makes impact with the earth and creates a giant tsunami.

This is the devastating moment when the smaller of the two comets, Beiderman, makes impact far out in the Atlantic ocean. The force of the impact would have been the equivalent of over a thousand Hiroshima bombs! Thankfully the Messiah crew managed to reduce the size of the comet by blowing it into two and now the impact of the smaller one was relativley smaller. In this picture, Beiderman can be seen bursting through the earths atmosphere.

The original comet, Wolf-Beiderman would have made impact somewhere in Texas and would have sent a great cloud of dust into the air. The 100 billion tonne comet would blot out the sun for 2 years with this impact and would end life as we know it. All plant life would die within 3 weeks and all animal life (including humans) would be gone within a few months. Surely an extinction level event.

Fortunatley the crew of the Messiah mission managed to blow up the larger comet, Wolf and gave the people of earth some hope.