There is a scientific consensus that climate change is happening. A rise in global temperatures is a documented fact - the world has already warmed about 1.1 degrees Celsius since the Industrial Revolution.
It is driven by carbon dioxide emissions
Most scientists agree that carbon dioxide (CO2) emissions have increased over the last few decades due to human activity. Burning coal, oil and gas spew carbon dioxide into the air, which then acts like a blanket to trap heat on Earth.
The Paris Agreement was set up to slow down those emissions
The 2015 agreement is a collective effort by all countries who are party to it to prevent the Earth from heating up by 2 degrees Celsius since the start of the industrial age – a difficult feat as the world has already warmed by 1.1 degrees since then.
Scientists have noted that the limits set for the climate accord are not good enough – that in order to curb climate change, more ambitious goals should have been set.
The increase in temperature is making its mark
Glaciers worldwide are melting, as are parts of Antarctica. Sea levels are rising and ice in the Arctic is at record low levels. Plants and animals are changing in their growing and migration habits because of shorter and milder winters. Extreme weather events such as El Nino are all the more severe because of the increasing heat.
As the ice melts, the water not only threatens to submerge major cities like New York and Mumbai but could also immerse countries like the Maldives.
Climate change will thaw permafrost, releasing a disastrous amount of methane into the air
Sometimes called a climate change time bomb, the northern hemisphere's 15 million square kilometres (six million square miles) of permafrost contains roughly twice as much carbon – mainly in the form of methane and (CO2) – as Earth's atmosphere.
If this methane and carbon dioxide gas were to be released into the atmosphere, it would speed up global warming drastically.
It is affecting the life in our oceans
Global warming turns the oceans acidic, reducing the ability for the body of water to play host to life but the rising temperatures also have an effect on coral, which are home to 25 percent of marine fish life. The Great Barrier Reef, which lines Australia's northeastern coast suffered its most severe bleaching on record last year due to warming sea temperatures during March and April.
Bleaching, occurs when abnormal conditions such as warmer sea temperatures cause corals to expel algae, draining them of their colour. They do not die, but are not healthy.
Corals can recover if the water temperature drops and the algae are able to recolonise them, but it can take a decade and is unlikely to do so with the way the oceans are warming up. At this rate, nearly all corals will be dead by 2050.
Climate change affects how much food is on the table in some countries
Droughts, heat waves and floods all have the ability to affect harvests and weather phenomena such as El Nino and La Nina have the potential to exacerbate them.
More than 20 million people across Nigeria, South Sudan, Somalia and Yemen, are in areas hit by drought and are experiencing famine or are at high risk of famine, according to UN numbers.
Air pollution kills
Scientists also say air pollution, caused largely by burning fossil fuels, not only contributes to climate change but is also exacerbated by it. As air stagnates soot, dust and ozone tend to build up in the lower atmosphere.
Exposure to high levels of air pollution, especially over the long term, can affect human respiratory and inflammatory systems, and can also lead to heart disease and cancer.
An estimated 6.5 million people were killed by air pollution in 2012, the latest data from the World Health Organisation (WHO) shows.