The United Nations' (UN) World Population Day is annually observed on July 11 to reiterate the human right to plan for a family. It encourages activities, events, and information to help make this right a reality throughout the world.

The Day was first marked on 11 July 1990 in more than 90 countries. Since then, a number of United Nations Population Fund (UNFPA) country offices and other organizations and institutions commemorate World Population Day, in partnership with governments and civil society. 

What are the causes of overpopulation?   

Overpopulation is mainly attributed to trends such as people living longer and enjoying higher live birth rates. Overpopulation of specific locations can also result from migration. Remarkably, the overpopulation of an area can occur without a net gain of population.

It can result from a reduction in the carrying capacity of a region, such as reduced agricultural yield due to over farming or drought. Such conditions may lead to an out-migration.

Facts about population   

• The world has added approximately one billion inhabitants over the last twelve years. 
• The world population is expected to reach 8.6 billion in 2030, 9.8 billion in 2050 and 11.2 billion in 2100. 
• 50.4 percent of the world’s population is male and 49.6 percent is female. 
• The global population was six billion in 1999 and seven billion in 2011. It is currently 7.43 billion. 
• Every second of every day, 4.2 people are born and 1.8 people die. 
• The UK population is 65.1 million which is only 0.88 per cent of the world’s total. 

What are the effects of population growth on our environment?   

The relationship between overpopulation and environmental impacts are often interrelated. here is some of the key sustainability challenges related to overpopulation.

Biodiversity

Due to his destructive activities, man has extracted more and more minerals from the earth. Animals have been hunted and plants have disappeared. There has been loss of biodiversity. These have led to ecological imbalance.

Deforestation

Human population increase is related to deforestation. More people mean we need more food, more wood products, and more firewood. Deforestation in turn leads to a reduced ability to capture CO2, thus exasperating the greenhouse gas problem. Tropical rainforests in South America are responsible for producing 20 percent of the Earth's oxygen. Deforestation is also strongly associated with loss of habitat and extinctions. Agriculture, as mentioned above, is responsible for about 80% of global deforestation. Another 14 percent is attributed to logging, 5 percent to firewood collection, and the balance resulting from other causes.

Degradation of the environment   

Climatic changes are irregular due to greenhouse gases.

With the overuse of coal, oil and natural gas, it has started producing some serious effects on our environment. Rise in the number of vehicles and industries have badly affected the quality of air. Rise in amount of CO2 emissions leads to global warming. Melting of polar ice caps, changing climate patterns, rise in sea level are few of the consequences that we might have to face due to environment pollution.