IELTS Reading: Climate Change

Paragraph A The scientific consensus on anthropogenic climate change is, by any measure, overwhelming. Since the late nineteenth century, average global surface temperatures have risen by approximately 1.2 degrees Celsius, a figure that, while modest in appearance, masks profound disruptions to atmospheric and oceanic systems. The Intergovernmental Panel on Climate Change (IPCC), in its Sixth Assessment Report published in 2021, concluded that human-induced warming is 'unequivocal', driven primarily by the accumulation of greenhouse gases — carbon dioxide, methane, and nitrous oxide — released through the combustion of fossil fuels, deforestation, and industrial agriculture. What distinguishes the current warming episode from natural climate variability, researchers argue, is both its pace and its origin: no comparable shift in global temperature has been recorded over such a compressed timeframe in the past 800,000 years of ice-core data.

Paragraph B Carbon dioxide remains the dominant driver of contemporary global warming. Atmospheric CO₂ concentrations, which hovered around 280 parts per million (ppm) throughout the pre-industrial era, surpassed 420 ppm in 2023 — a level not encountered on Earth for at least three million years, according to paleoclimatological reconstructions. The relationship between CO₂ and temperature is well established: the gas absorbs and re-emits longwave radiation, effectively insulating the planet in a manner analogous to a greenhouse. What is less commonly appreciated, however, is the concept of 'carbon lock-in'. Even if all anthropogenic emissions were to cease tomorrow, the thermal energy already absorbed by the oceans would continue driving warming for several decades, a phenomenon climate scientists refer to as 'committed warming'. This inertia within the climate system means that the consequences of past emissions are, to a significant extent, already written into the planet's future.

Paragraph C Among the most tangible and far-reaching consequences of global warming is the accelerating rise in sea levels. This process operates through two principal mechanisms: the thermal expansion of seawater as it absorbs heat, and the melting of land-based ice, particularly from the Greenland and Antarctic ice sheets. The IPCC projects that, under a high-emissions scenario, global mean sea levels could rise by as much as one metre by 2100, threatening coastal populations numbering in the hundreds of millions. A study conducted by researchers at the University of Utrecht in 2022 found that low-lying delta regions in South and Southeast Asia face disproportionate risk, with some areas potentially experiencing annual flooding by mid-century. Crucially, the report noted that even under optimistic mitigation scenarios, a rise of at least 0.3 metres appears unavoidable — a direct consequence of the committed warming described above.

Paragraph D The political response to these findings has been, at best, uneven. The 2015 Paris Agreement represented a landmark moment in international climate diplomacy, committing signatory nations to limiting warming to 'well below' 2 degrees Celsius above pre-industrial levels, with efforts directed towards a more ambitious ceiling of 1.5 degrees. Nevertheless, independent analyses by organisations such as Climate Action Tracker have consistently found that the aggregate of national commitments — known as Nationally Determined Contributions, or NDCs — falls considerably short of what would be required to meet these targets. As of 2023, current policies were projected to result in warming of approximately 2.7 degrees by 2100. Critics argue that the voluntary, non-binding nature of the Agreement's enforcement mechanisms renders it structurally incapable of delivering the scale of emissions reduction that the science demands.

Paragraph E Proponents of ambitious climate policy contend that the economic case for rapid decarbonisation is, in fact, compelling. The Stern Review on the Economics of Climate Change, first published in 2006, argued that the costs of inaction would far exceed the costs of mitigation — a conclusion subsequently reinforced by numerous economic modelling studies. The transition to renewable energy, the electrification of transport, and the retrofit of building stock are increasingly regarded not merely as environmental imperatives but as drivers of economic growth and employment. Yet sceptics within policy circles caution that the distributional consequences of such transitions must not be overlooked; communities historically dependent on fossil fuel industries face acute social and economic disruption, a challenge that has come to be framed under the concept of a 'just transition'. How governments balance urgency with equity may ultimately determine whether climate commitments translate into durable policy or remain, as some observers have suggested, aspirational declarations detached from structural reality.