Our climate is changing everyday. Humans have caused major climate changes to happen already. Changes that is observed over the 20th century include increases in global average air and ocean temperature, rising global sea levels, reduction of snow and ice cover, and changes in atmospheric and regional weather patterns, which influence seasonal rainfall conditions.
These changes are caused by extra heat in the climate system due to the addition of greenhouse gases to the atmosphere. The additional greenhouse gases are primarily due to human activities such as the burning of fossil fuels (coal, oil, and natural gas), agriculture, and land clearing. All these activities increase the amount of heat-trapping greenhouse gases in the atmosphere. The evidence of climate change is supported by extensive scientific research performed and reported across the world. Climate models are used to understand the causes of climate change and to project changes into the future. However, if we stopped emitting greenhouse gases today, the rise in global temperatures would begin to flatten within a few years. Temperatures will be the same or might not change a lot ,but will remain well-elevated for many, many centuries. Climate change pose risks to human and natural systems, through more frequent and severe heat waves, coastal inundation due to sea level rise, disruptions to rainfall patterns and other effects. There is a time lag between what we do and when we are going to feel the effects, but it is knocking at our doors !!
Analyses of a range of climate scenarios indicate the most severe risks of climate change can largely be mitigated if greenhouse gas emissions are reduced to the point they are no longer accumulating in the atmosphere.
What is Greenhouse effect that everyone talks about? In simple terms the greenhouse effect is a natural process that warms the Earth’s surface. When the Sun’s energy reaches the Earth’s atmosphere, some of it is reflected back to space and some is absorbed and re-radiated by greenhouse gases. Greenhouse gases include carbon dioxide, methane, nitrous oxide, ozone and some artificial chemicals such as chlorofluorocarbons (CFCs).
The absorbed energy warms the atmosphere and the surface of the Earth. This process maintains the Earth’s temperature at around 33 degrees Celsius warmer than it would otherwise be, allowing life on Earth to exist.
Without major action to reduce emissions, global temperature is on track to rise by 2.5 °C to 4.5 °C (4.5 °F to 8 °F) by 2100, according to the latest estimates.
Particularly burning fossil fuels agriculture and land clearing – are increasing the concentrations of greenhouse gases. This is increasing the greenhouse effect, which is contributing to warming of the Earth.
Its not not be too late to avoid or limit some of the worst effects of climate change. We can have two step approach reducing the flow of greenhouse gases into the atmosphere. Learning to live with, and adapt to, the climate change that has already been set in motion.
Read more about NASA's efforts to address climate change at