<P> Ozone depletion describes two related phenomena observed since the late 1970s : a steady decline of about four percent in the total amount of ozone in Earth 's stratosphere ( the ozone layer ) , and a much larger springtime decrease in stratospheric ozone around Earth 's polar regions . The latter phenomenon is referred to as the ozone hole . There are also springtime polar tropospheric ozone depletion events in addition to these stratospheric phenomena . </P>
<P> Ozone depletion describes two related phenomena observed since the late 1970s : a steady decline of about four percent in the total amount of ozone in Earth 's stratosphere ( the ozone layer ) , and a much larger springtime decrease in stratospheric ozone around Earth 's polar regions . The latter phenomenon is referred to as the ozone hole . There are also springtime polar tropospheric ozone depletion events in addition to these stratospheric phenomena . </P>
we are concerned about ozone depletion in what layer of the atmosphere
we are concerned about ozone depletion in what layer of the atmosphere
stratosphere
stratosphere