Indiscriminate burning of fossil fuels – oil, coal and natural gas – has increased greenhouse gases in the atmosphere to a new high, bringing with it the risk of rapid human-driven global warming. Data collected by the UN’s Inter-governmental panel on Climate Change (IPCC) has revealed that temperatures are set to surpass the maximum temperatures in the 11,300-year period known as the Holocene – all plausible greenhouse gas emission scenarios.
The increasing greenhouse gas concentrations in the atmosphere combined with a leveling off or decline in sulphate aerosols – which tend to offset the warming effects of greenhouse gases – will result in disruptive and unpredictable changes in global weather patterns during the next decades. Floods, droughts, wild fires and heat wave outbreaks will likely become more frequent as temperatures rise, a new study suggests.
Another study has warned that climate change is set to trigger more frequent and severe heat waves in the next 30 years regardless of the amount of carbon dioxide (CO2) emitted into the atmosphere. Extreme heat waves such as those that hit the US in 2012 and Australia in 2009 – dubbed three-sigma events by the researchers – are projected to cover double the amount of global land by 2020 and quadruple by 2040. And meanwhile, more-severe summer heat waves – classified as five-sigma events – will go from being essentially absent in the present day to covering around 3 per cent of the global land surface by 2040.
The study published in the journal Environmental Research letters, found that in the first half of the 21st century, these projections will occur regardless of the amount of CO2 emitted into the atmosphere. After then, the rise in frequency of extreme heat waves becomes dependent on the emission scenario adopted. Under a low-emission scenario, the number of extremes will stabilize by 2040, whereas under a high-emission scenario, the land area affected by extremes will increase by one per cent a year, after 2040. According to researchers, under a high-emission scenario, the projections show that by 2100, three-sigma heat waves will cover 85 per cent of the global land area and five-sigma heat waves will cover around 60 per cent of global land.
Besides, most research on climate change had forecast a global sea-level rise of half a metre (over 1.5 feet) by 2100. Now, new projections show that by 2050, if not sooner, the world’s oceans will rise above a metre and this will be just enough to inundate the Maldives, parts of Bangladesh, a large number of Pacific islands and many low coastal areas in the US, Asia and other regions. This is primarily expected due to the melt rate of glaciers in the fastest melting part of Antarctica has tripled over the past decade, revealed an analysis of the past 21 years. The study published recently concluded that the melting of glaciers in West Antarctica, which contains enough water to raise sea levels by atleast a metre, is speeding up and seems irreversible.
Climate change, has also resulted in adverse effects on marine ecology. The ocean system, which regulates the global temperature and atmosphere, feed billions of people, and largely determine our weather, is under severe threat due to increasing emission of greenhouse gases.
One of the most stunning conclusions in a recent major report of the UN’s inter-governmental panel on climate change (IPCC) is that ‘the current rate and magnitude of ocean acidification are at least 10 times faster than any event within the last 65 million years’. The IPCC, which evaluates the peer-reviewed scientific literature, has warned that the situation is disastrous as many of the benefits of our oceans (coral reefs, fisheries, coastal living, et all) would be transformed beyond recognition, if we fail to act on climate change decisively.
Pollution and climate change has already killed marine life in the last four decades, according to a recent report of the World Wide Fund for Nature (WWF). Species essential to global food supply – especially in poorer nations where fish provides essential dietary protein – were among the hardest hit. The family of fish that includes Tuna and Mackerel, for instance, has declined by three quarters since 1970, the conservation group’s Living Blue Planet Report said.
According to the report, fish are not the only marine organisms in steep decline, large swathes of coral reef, mangroves and sea grasses have died. This loss has decimated fish populations and, in turn, imperiled some 850 million people who depend directly on these ecosystems for their livelihoods. Half of all coral has already disappeared, and the rest will vanish by 2050 if temperatures continue to rise at current rates, the report warned.
At the same time, the volume of marine life is diminishing, so too is the number of species, both in the ocean and on land. This alone should be the reason to act decisively on fossil fuel emissions and other drivers of climate change, researchers said.
Indeed, scientists believe Earth has entered a sixth ‘mass extinction event’, with species disappearing 100 times more quickly than only a century or two ago. Experts pointed out that there have been five such episodes over the last half-billion years, the most recent was wiping out of all non-avian dinosaurs and most other form of life – the mass extinction and ecological collapse, some 65 million years ago.
(The Writer is a freelance journalist)
