Human- Induced Climate Change Why You Should Take It Seriously

Abstract

As the title suggests, the objective of this chapter is to outline the reasons why you should take the issue of human- induced climate change seriously. There is no doubt that the concentrations of a number of the key components of the atmosphere, so-called greenhouse gases with the potential to alter climate, are higher now than they have been at any time over at least the past 800,000 years, probably much longer. Furthermore, there is no question but that diverse forms of human activity are largely responsible for the recent increase in the concentrations of these gases. The increase began several hundred years ago and, unchecked, is likely to continue into the indefinite future. This alone should justify a cautionary response with respect to the prospects for human-induced climate change. But, as we shall see, the issue is even more complicated. The warming impact of the rising concentration of greenhouse gases has been offset (muted) until recently by cooling resulting from small particles formed in the atmosphere as byproducts of conventional forms of air pollution. These particles, referred to as aerosols, have an important negative impact on public health: when respired, they persist in your lungs and can enter the bloodstream, triggering a variety of serious cardio-vascular and respiratory problems. They contribute also to the phenomenon of acid rain responsible for killing freshwater fish and damaging plant life more generally. Societies have taken steps with some success to reduce emissions of these offending chemicals. The downside is that we are now beginning to experience acceleration in the pace of climate change, a circumstance for which we are ill prepared. I begin with a discussion of the energetics of the global climate system, the situation that would apply if energy absorbed from the sun on a global scale were balanced precisely by energy returned to space in the form of long- wavelength (infrared) radiation, following with an account of what we understand when we talk about the greenhouse effect, the role played by specific components of the atmosphere in limiting transmission of infrared radiation to space.