Conjunctive adverbs are also known as adverbial conjunctions. The reason is that they, too, are used to join two closely related independent clauses. However, they cannot be punctuated like conjunctions.

When you use a conjuctive adverb to join two independent clauses, the punctuation should be as follows: semicolon|adverbial conjunction|comma.

Why do we use conjunctive adverbs? Why don’t we just use conjunctions? Well, the simple explanation is that adverbial conjunctions sound more formal. But, the real reason is that they lend more emphasis to the clause to which it is attached.

Here is an example:

Our meal was late, and it was overcooked.
Our meal was late; furthermore, it was overcooked.

There are many different adverbial conjunctions that perform different duties to help writers lead their readers in different directions. Here they are:

To add to an idea: likewise, also, in addition, besides, furthermore, and moreover
To show results: thus, therefore, accordingly, hence
To contrast: however, nevertheless, nonetheless, consequently
To show time: meanwhile
To show emphasis: indeed, in fact
To show likeness: likewise, similarly
To show an alternative: otherwise, instead, on the other hand

Just remember that when you are joining two independent clauses with one of these, insert a semicolon before it and a comma after it. If you simply place a comma before it, then you have just made a comma splice error.