Avoiding catastrophic effects of climate change means we need to keep the temperature rise under 2ºC globally. This 2ºC mark has become a rallying point for international and national action, but we don’t know if we’ll be able to keep to this limit. In most places, daily variations in temperature far exceed 2ºC, so imagining long-term, global change caused by a ‘mere’ 2ºC is difficult. We’re fast approaching that 2ºC global limit – we could hit it by 2060.
Climate is complex but also ‘lethargic’ – change is slow, so immediate action (or inaction) will have long-term impacts not necessarily immediately visible. The oceans, for instance, are where 90% of warming is occurring, at the rate of four Hiroshima bombs per second, but they will take many decades to warm. One way of visualising the long-term impacts of small-seeming changes is to liken the globe to an icebox at a party: left open, the ice melts but slowly, and the water is fairly cold. But eventually the water grows warms and so do the drinks in the box. Some scientists predict we’ll never see another ice age – ever. So this is all the ice we have, and once melted it will not re-form.
- The Conversation: Two degrees: how we imagine climate change