Most organisms on earth spend large amounts of energy reproducing sexually, instead of using a more efficient method of asexual reproduction. finding and competing for mates, meiosis and gamete production, and the complexities of fertilization could all be avoided if asexual reproduction was sufficient. why isn't it?

Sexual reproduction confers a big advantage over asexual reproduction. This advantage is the possible variations in offsprings. This allows natural  selection to act upon several genotypes and phenotypes and have the most adapted one to pass its genes to the next generation  hence giving the population the capacity to survive any changes in the environment.

it would affect precipitation by causing flooding in some areas of the world due to climate increasing, causing the glaciers in the northern and southern pole of our planet to melt.

i wish you would have provided choices to simplify it and allow me to give an exact answer.