For moral statements to be pure emotion is an emotive view of ethics. Emotivists believe that moral decisions or statement should be made based on emotion. A philosopher who believed very strongly in the emotivist theory was G.E Moore. Moore states that when people use the term 'right' or 'wrong' they are stating there feelings towards the action issued. However since different persons have different feelings. The conclusion of moral decision cannot be either 'right' or 'wrong' but both.
If moral statements were based purely on emotion, and emotions are hidden in them. Then morals can change on a daily basis, and are as easy to make as choosing what you are going to have for lunch. E.g. if a woman wanted to have an abortion, and her decision was purely based on her emotion at that time. It is not a stable decision as her emotions are changing, due to her hormonal changes, because of the pregnancy.
A massive floor in the emotive argument is that you can never reach a decision on whether something is morally right or wrong. Thus creating problems in law, and common ethical dilemmas such as abortion, euthanasia and animal rights.
The emotive view comes under the umbrella term non-cognitive. Other views that also come under the same term, are relativism and subjectivism. Relativism is the view that making a moral decision it is based on your culture and settings, or even upbringing. Subjectivism is the view that when making a moral decision it is based on feeling, and personal taste which again can vary dramatically.
The main criticisms of all the non-cognitive views is that we can make moral decision without any emotion at all E.g. a judge can sentence a man to the death penalty in some American states. Thus they are making this moral decision purely on the law and the fact that it is his/her job.
So the implications to ethics if all our decisions were made based on emotion or non-cognitive views, would be that peoples views and