Here's a quick explainer.

Climate change is a broader term that covers changes including global temperature rise, changes in sea level due to shrinking ice sheets and glacial retreat, extreme weather events, vanishing species and shifting rainfall patterns. If the greenhouse gas emissions continue at the current pace, the temperatures can exceed 2-3 degrees over the next century, which would undermine our planet’s capacity to support human population.

2 degrees is actually a significant amount.

The Earth has warmed by more than 1 degree celsius (2 degrees Fahrenheit) since 1880. The number may sound low but is significant as an average over the surface of an entire planet and it takes a vast amount of heat to warm all the oceans, atmosphere and land by that much. This explains the reason why much of the world’s ice has started to melt and oceans are rising at an accelerating pace.

We’ve known about it for more than a century.

Scientists in the 19th century discovered that a certain type of gases in the atmosphere trap heat that would otherwise escape to space. Carbon dioxide is a major player and without any of it in the air, the Earth would be a frozen wasteland. However, the gas has increased 43 percent above the pre-industrial level as humans release more carbon dioxide into the atmosphere every year, and the Earth has warmed by roughly the amount that scientists predicted it would.

Nope.

Greenhouse gases levels have risen and fell naturally in the long-ago past, but that takes thousands of years. To distinguish industrial emissions from natural emissions, hard evidence studies using radioactivity suggest that humans are pumping greenhouse gases into the atmosphere much faster than nature has ever done.

Because of ideology.

Instead of negotiating climate change policies, a lot of political conservatives are trying to undermine the science behind climate change with the backing and lobbying from oil and coal companies. These companies heavily finance the campaigns of politicians who push their agenda at global level. Some have even claimed that that scientists are engaged in a worldwide hoax to fool the public.

The predictions are not perfect, but they’re grounded in solid science.

The reality is we are already feeling the effects, whether we know it or not. Thousands of people are dying in heat waves made worse by global warming. Due to increase in sea level caused by meting of polar ice caps, homes of lakhs of residents in coastal areas are getting flooded every year. Scientists have calculated this would not be a case in a stable climate.

In most cases, yes.

Scientists worldwide have published strong evidence that the increase in frequent and intense heat waves is tied to warming of our climate. This is also resulting in heavier rainstorms, coastal flooding, hurricanes and severe drought conditions in many parts of the world.

Yes, but change is happening too slowly.

We as a society have been so late to act that the risks are now severe, scientists say. But if we still stop burning fossil fuels, it’s not too late to act. The warming will reduce to a manageable pace when human emissions are reduced to zero. The reforms that needs to be adopted by all countries include fuel-economy standards for cars, stricter building codes and emissions limits for power plants. But this transition need to happen quickly to avoid the worst effects of climate change.

Sales are still small overall, but they are rising fast.

The cars draw power from electric grid and have no pollution effect as they move around the cities and towns. They are more efficient than petrol cars and will be hugely important when the electric grid itself becomes greener through renewable energy. Infact, the advancement in electric cars is happening at such a rapid pace that some countries are already talking about banning the sale of petrol cars after 2030.

You can start by first sharing this with all of your friends.

The problem can only be solved by large-scale, collective action. All nations have to clean up their energy systems as quickly as they on. The most important thing you can do is to speak up and demand change.