What is Global Warming ?
The average temperature on our Earth is rising continuously. This is known as Global Warming. The reason behind the rise in the global temperature is the released greenhouse gases by burning fossil fuels.
Whenever and wherever the word ‘Earth’s temperature’ is used it means that the temperature of the surface of the earth. The Earth’s surface is made up of land surface and the surface of the ocean. Global warming is leading to the rise in both land surface and the surface of the ocean.
Rise in average temperature is leading to the changes in the climatic system of the Earth.
Is climate really changing?
What are the evidences?
Is there any scientific proof present to prove that global warming is happening?
To answer these queries United Nations has set up a panel called ‘Intergovernmental Panel on Climate Change (IPCC)’. The panel comprises of hundreds of climate scientists from around the world.
The scientists working for IPCC gather the global data and state of the art research on global temperatures, climate change and its impact. Based on the assessments of these data and research, IPCC publishes its Assessment Reports.
According to the fifth assessment report (AR5) of IPCC ‘CLIMATE CHANGE 2014’ there is no doubt that the climate system is warming.
The report confirms that the global warming has already resulted in the warming of the atmosphere and the ocean, decline in the snow and ice from the earth surface and rise in the sea level.
How do we know that the average temperature on Earth is increasing? What are the Global Warming Trends:
It is tough to come to a conclusion about the Global warming. To know weather or not the Earth’s temperature is rising, various comparisons are made.
(i) The 20th century global average surface temperature is 13.9 °C (57.0 °F). One way is to compare each year’s average with this one.
(ii) Compare the Global average temperature of each decade and check if it is following any trend.
(iii) Set a long term baseline temperature of 30 year and compare each years individual temperature with the base line.
Global Warming Trends Prove that it is Real:
Given below the Global warming trends that have come up using these comparisons:
1. What information the Graph ‘Global Land and Ocean Temperature Anomalies’ gives us?
NASA started keeping the global temperature records in 1880. It means that the global temperature data of last 136 years is present. This data is assessed and the trends are interpreted. This helps in giving the answer of the question weather or not the Global warming is real?
The global average temperature of the 20th century across land and ocean surface was found to be 13.9 °C (57.0 °F). The graph has been plotted against this values in the X axis. ‘Anomalies’ refers to any deviation from this average value. with respect to the global average temperature of the 20th century, the average temperature of all the years between 1880 to 2016 was plotted.
The blue bars are the years when the average global temperature was below the 20th century average, while the red bars show that the average temperature of that particular year was above 20th century mean.
This graph shows that before 1940, the average temperature was always below the 20th century mean temperature. During the mid 20’s the temperature started going above the mean temperature of 20th century while post 1980 there is not even a single year when the average temperature did not go above the 20th century average.
All the years post 2080’s have average temperature above the 20th century mean.
2. The temperature data of the last 136 years tells that the global average temperature of the earth is rising at the rate of 0.07°C (0.13°F) per decade. Hence each successive decade has been warmer than its previous decade. And this is a matter of great concern.!
The average temperature rise of 0.07 °C per decade may seem insignificant. But science says it is not!
The reason is that the rate of temperature rise per decade is not equal.
During the initial decades when the record keeping begin the rate of global average temperature rise was way less than the later decades.
The overall rate of increase in the globally averaged temperature is 0.07°C (0.13°F) per decade since 1880. But, the rate in the later part of the 19th century (since 1970) is 0.17°C (0.31°F) per decade.
3. How much is the Earth’s temperature rising each year?
As an estimate by NASA, the Earth’s average global temperature has increased by about 0.8° Celsius (1.4° Fahrenheit) since 1880.
Another fact that support that Global Warming is real is that 15 out of the 16 warmest years so far have happened during the 21st century. The only exception is the year 1998 which holds the 6th position in the list of warmest years so far.
Among the warmest years across land and ocean surface, 2016 holds the first position. It broke the records set by the year 2015 which in turn had broken the warmest year’s record set by 2014. It means that last 3 years have been successively the warmest years.
In order to analyse the global average temperature rise, the scientists compare the short term climate data with the long term data. Generally the long term data consists of 30 years. For example the thirty year period between 1940-1970 or 1950-1980 or 1960-1990 may be taken as base year and used for reference.
The globally averaged temperature of each year across land and ocean surface is measured. Separately the yearly averaged global land surface temperatures and yearly averaged global ocean temperatures are also measured. These are compared with the base year to come to a conclusion. Following are some of the Global warming trends:
According to both NASA and National Oceanic and Atmospheric Administration (NOAA), 2016 has been the warmest year on record so far. The average temperature of 2016 was 0.99 oC (1.78 degrees Fahrenheit) warmer than the 1951-1980 average temperature.
The average temperature of 2016 was 0.04°C (0.07°F) higher than the previous record set by the year 2015.
According to UK Met Office the average temperature of Earth in 2015 was 0.75 oC higher than the long-term average of 1961 and 1990 (14.0 °C). The year 2015 broke the record of the warmest year set a year ago by 2014 when the average temperature was recorded to be 0.57 oC higher than the long term average. (Source: UK Met Office).
As compared to the 20th century average ocean surface temperature the average ocean surface temperature of 2016 around the world was 0.75°C (1.35°F) higher.
A year before, in 2015, the ocean surface temperature was found 0.74 °C (1.33°F) higher compared to the 20th century average ocean surface temperature.
2016’s ocean surface temperature left behind the previous record set a year ago in 2015 by 0.01°C (0.02°F). 2015, in turn, had left behind the previous record set by 2014 by 0.11°C (0.20°F).
Similarly, the global annual land surface temperature for 2016 was 1.43°C (2.57°F) above the 20th century average leaving behind the previous record of 2015 by 0.11°C (0.19°F).
This Shows that the Earth’s Globally averaged Surface temperature, global average temperature for oceans and global average temperature for land surface are rising.
Click here to know about Global Warming Statistics 2017.