Punctuation is essential to convey meaning while writing. Read this notorious example of how punctuation can change the whole meaning of a sentence.

• A woman, without her man, is nothing.
• A woman: without her, man is nothing.

I could argue that neither is correct, but that’s for a different type of article. 

Punctuation matters.

In IELTS, punctuation mistakes can hurt your score badly. 

Read this excerpt from the writing task two band 7 descriptor:

Grammar and punctuation are generallywell controlled, and error-free sentences are frequent.

So, let us start.

1. Commas (,)

Commas can take three places in a sentence: introducers, coordinators, inserters, and tags. 

• Introducers

Commas could introduce words, phrases, dependent clauses and even direct quotation.

• • Words

Global warming is becoming an international concern. Thus, scientists are studying ways to mitigate its dire consequences. Obviously, those scientists would need funds to support their research. 

• • Phrases

As a result, governments of the world should impose laws to limit the emissions of CO2 into the atmosphere.

Having said that, there also should be laws regulating the production of plastic.

• • Dependent Clauses

Because the effects of global warming are felt on daily basis, there should immediate measures taken. 

• • Direct Quotations

“The world has reached irreversible damage because of global warming,” said one scientist.

• Coordinator Commas
  • Commas are used to link two independent clauses that are joined with a coordinating conjunction to create compound structure. 

Companies realize the problem with burning fossil fuels, yet they continue using it as a main source of energy. 

• • Commas are used to list a series of more than two things of something. (Make sure it is parallel.)

There are plenty of reasons behind global warming: human activity, greenhouse effect, and the industrial revolution. 

• Inserter Commas

Inserter commas are used to add an extra piece of information within an independent clause. It could be removed without affecting the meaning. 

• • Words

 Petrolum companies, however, ignore the warning from scientists on the imminent danger of global warming.

• • Phrases

Clothing companies, on the other hand, produce too much waste which poses another serious threat to the environment. 

• • Nonrestrictive phrases and clauses

Scientists, who work day and night to find alternative fuel, have taken the full responsibility of saving our planet.

• Tag Commas

They mainly come at the end of the sentence.

• • Words

Rising sea levels threats coastal cities, too.

• • Phrases

Miami is facing an imminent threat of flooding, for example. 

The wealthy have secured themselves, leaving the rest of the world suffering the consequences.

2. Semicolons (;)

A semicolon is not like a comma, but rather a period.

• It is used to link two independent clause with close meaning without the need to use a coordinator.

Global warming is real threat to all living beings on earht; it causes desertification which can result in the extinction of some animals.

• Before conjunctive adverbs and transition phrases, we can use a semicolon. However, many writers nowadays use a period and just start a new sentence with an introducer comma after the transition phrase and the conjuntive adverb.

Global warming can cause extinction of some animals; therefore, there should be some immediate measures to be taken.

Global warming can cause extinction of some animals; in fact, if no measures were to be taken soon, we may witness the disappearance of some species in recent generations. 

The previous sentences could be written differently as follows:

Global warming can cause extinction of some animals. Therefore, there should be some immediate measures to be taken.

Global warming can cause extinction of some animals. In fact, if no measures were to be taken soon, we may witness the disappearance of some species in recent generations. 

• Between items within a list, we can use semicolons if commas are already included.

There are numerous consequences for global warming: water shortages, which are becoming more frequent than ever before; rising sea levels, which threats the lives of those living in coastal cities; and other natural disasters such storms, floods and droughts.

We don’t normally use listing in our IELTS writing, and it is safer not to use semicolons in general. Many modern writers avoid using them.