This essay is good. However, I have a few points to share:
can't
no contracted form. Write cannot
put their efforts
initiate efforts / make an effort
In the other words
In other words
Start from replacing the use of private transport by using public ones, each citizen has contributed to reduce the carbon dioxide emission on Earth.
This interrupts the flow. If you could, rewrite this sentence.
Plus
Well, you'd better present the other ones with academic tone. There are many common linkers or appropriate conjunctions.
Take my school as an example, twice a semester, students are encouraged to join the event titled "Plant tree, build future" to plant at least one tree in school back yard. This event is truly helpful in teaching students the importance of planting trees and conserving our globe.
if you present an example, try to write it clearly. To have one, you should ask some journalistic questions: how many? how? who? what? when? results?. By this, I am sure that you will have details as to support the topic sentence.
Have look at this "specific example":
Many everyday practices are now performed by machines instead of people and this has resulted in less need for labour.
For example, in recent decades nearly all major banks have replaced telephone operators with telephone switchboards that have recorded messages and all banks now have automated teller machines (ATMs). This reduces the need for people to visit the bank itself and has resulted in a corresponding decrease in the need for the bank staff. As bank and other similar business strive for profit, this is likely to increase unemployment further in the future.
Who? Banks
How many? nearly all
When? Over the last few decades
What? Replaced need for telephone operators and bank tellers
How? Using switchboards and ATMs
Result? People don't need to visit the bank and less staff are needed
When you deal with IELTS, the first thing the assessor sees is your layout, which shows whole of your essay. If the layout is difficult to read, which is let's say: no spaces between paragraphs, then he/she immediately knows your writing needs more work to read. Hence, I suggest you to leave one space every time you open a new paragraph.