Читать книгу Carbon Counter - Mark Lynas - Страница 18

You might have noticed from the discussion above that there are certain ‘tipping points’, after which global warming could become unstoppable. Several of these could be reached if temperatures cross the two degrees threshold, because at this level of warming, greenhouse gas releases from the soils and forests could take on their own unstoppable momentum. That would leave humanity powerless to intervene as our planet began cooking. For this reason, many environmental groups and even governments (including the European Union) have begun to fix on the target of two degrees as a danger level that must not be crossed.

The graph on pages 20-1 shows how high temperatures might rise, in comparison to their levels over the last millennium. Note that the two degrees danger line is well below most of the scenarios for temperature change by 2100.

Staying below two degrees with any level of certainty would require global greenhouse gas emissions to peak by 2015 – quite a tall order, especially given the reluctance of many people and nations to face up to the scale and urgency of the problem. However, even if we overshoot this target, any cuts we do make will still help to slow the rate of change. At the very least, this gives human societies and natural species more time to adapt to rising sea levels, harsher weather and shifting climate zones. So it’s not too late to act, but time is rapidly running out, and the era of procrastination is definitely over.