The climate system on which we depend for everything is breaking down before our eyes. The scale and speed of what is happening is truly terrifying and requires an emergency response that jolts us out of our inaction.<\/p>\n
Some scientists knew about the relevant atmospheric physics as far back as the 1850s. The oil industry also commissioned its own research in the 1970s, which made clear the risks \u2013 a Harvard analysis found internal projections made by ExxonMobil from 1977-2003 were \u201cshockingly\u201d accurate \u2013 but the industry decided to keep the information to itself. It was only in 1988 that the alarm was properly raised when the Intergovernmental Panel on Climate Change (IPCC) was established and James Hansen, director of the Nasa Goddard Institute for Space Studies, set out the principles of climate science in a US Senate hearing<\/a>.<\/p>\n Those key principles soon became incontrovertible and verified by every credible test. However, the timing was still somewhat uncertain. The assumptions involved in climate modelling made it hard to judge exactly how our complex planetary systems would work in this fast-changing world. Unfortunately, it now seems that the models underestimated rather than exaggerated the problem. <\/p>\n Real-time measurements mean we are no longer just modelling what might happen. The latest data shows we are experiencing an acceleration in the rate of climate change<\/a>. <\/p>\n Extreme weather events supercharged by the rise in temperatures are impacting on biosystems in a way that leads to the release of further emissions \u2013 such as the recent forest fires<\/a> happening right across the globe. There is a risk it could become a runaway phenomenon, and we will only know if we\u2019ve crossed a tipping point after the fact because of the time lags involved. <\/p>\n Hansen was one of the first to raise the alarm about this acceleration. Nearly four years ago, he was lead author in a paper thatargued the IPCC\u2019s assessment of the scientific literature for temperature increase was too optimistic and had underestimated the climate sensitivity of our planet. It presented findings that showed how our oceans, ice sheets and cloud systems were already changing in response to the existing increase in temperatures, which in turn is altering how much solar energy is being retained on our planet, rather than reflected out into space. <\/p>\n It also argued that a recent reduction in sulphur emissions from ships\u2019 engines and power stations \u2013 which had been introduced for good health reasons \u2013 was having inadvertent consequences. Those particles had a short-term effect in reflecting some solar energy away from Earth, which masked the longer-term energy imbalance that was taking hold.<\/p>\n Finally, it presented \u201cpaleoclimate\u201d data from ancient ice cores that showed our planet was historically climate sensitive. This has implications for our assumptions today. <\/p>\n The analysis was attacked at the time by the usual climate deniers and even questioned by some fellow scientists, but is now looking increasingly prescient. In March this year, a study supported<\/a> his argument, showing the temperature rise had almost doubled in the last decade.<\/p>\n