What is global warming? This is a fair question, as much is written and said about “global warming”. The term is often misused and people tend ask questions like, ‘do you believe in global warming?’ This is a bit like someone asking an economist, whether they believe in inflation. It is difficult to know where to start when answering, What is Global Warming? This is because there are other hidden questions buried in the original one. Many people when asking the first question, are often also wanting to know if the warming is attributed to human activity ( anthropogenic ); are greenhouse gases building up in the atmosphere?; and is the warming something they should be concerned about? The short answer to all those questions is YES!
Climate change has become a big political issue and a great deal of debate continues about the solutions. One approach being considered to reduce global carbon emissions is the idea of contraction and convergence . Under this approach all countries would participate in a global emission reduction with quantified emission targets.
Scientists use “global warming” in a precise way, to mean “a tendency for the globe to warm over a given period”. There is a great deal of scientific study focused on climate change, and the majority of scientists agree that the average global temperature is increasing. Check out some definitions of global warming here.
‘What is Global Warming’, is only part of the story and it doesn’t tell us when this might happen. What we do know is that global warming has occurred in the past, and it is also happening right now.
Undoubtedly the temperature of the globe has fluctuated since the very beginnings of our planet. The real problem is not just the fact that it is warming, but the rate at which it is warming. The ten warmest years since global temperatures have been measured all occur within the last 12-year period between 1997-2008*.
But that is the recent past, and scientists are suggesting that the current rapid rate of warming has no parallel within the last million years. Even when the globe did warm towards the end of an ice age the process was very gradual, warming up over a period of about 5,000 years. Our Earth is heating up, and heating up quickly.
The atmosphere surrounding the earth is mainly composed of Nitrogen (about seventy eight percent, and Oxygen (twenty one percent) with water vapour and various trace gases making up the rest. There are quite a few trace gases, such as; Argon, Carbon Dioxide, Neon, Helium, Methane, Hydrogen, Nitrous Oxide and Ozone. These gases, are often called green house gases because during the day the earth soaks up heat, and these gases act like a greenhouse trapping in the heat. Some of the heat is radiated back out into space, and if weren’t for these gases things would freeze over during the night. The issue of course is the increase in greenhouse gases, which is trapping in more heat, and causing a rise in global temperature.
The proportion of greenhouse gases has increased significantly since the Industrial Revolution (about 1750), and global carbon dioxide (CO2) concentration has risen 37 per cent, methane 150 per cent and nitrous oxide 18 per cent**. As the Revolution took hold humans began burning fossil fuels, (particularly coal) in a big way, to drive steam engines for industry, and generate electricity. When fossil fuels are burnt or combusted, carbon dioxide, methane and nitrous dioxide are given off as gases. In addition to escalating coal use after the Industrial Revolution, came the widespread use of another fossil fuel; petroleum for transport. At the beginning of the 20th century, annual global oil output was about 150 million barrels of oil, now, that amount is extracted globally in just two days. Burning fossil fuels releases billions of tonnes of carbon dioxide that has been locked away in the Earth for millions of years. Humans are adding billions of tonnes of carbon dioxide to the atmosphere each year, and guess what? Carbon dioxide is a greenhouse gas.
The rate at which the planet is warming is possibly the single biggest challenge to ever face humanity. The impacts are likely to devastating, we need to act decisively, and act now. A single web page cannot fully answer the opening question, what is global warming? Following the links on this page will allow you to see how complex and serious the issue of global warming is. So what is global warming? It is a disaster of our own making, that’s what. A smart idea would be to stop cutting our forests down, but what if we had algae farms feeding of the coal stacks and made biodiesel and health foods?
* See report at http://data.giss.nasa.gov/gistemp/2008/
** CSIRO, Human Activities Are Changing the Climate, http://www.csiro.au/resources/Humans-Changing-Climate–ci_pageNo-2.html