It appears mankind has harmed the environment beyond repair. Greenhouse gases in the atmosphere have reached levels where their adverse effect is almost impossible to reverse. However, concerted efforts can still restore some balance, though it will take decades and centuries.

Climate change is intensifying, occurring at an accelerated pace and is already affecting every region of the planet. It is changing Earth in ways that are unprecedented in thousands of years, and in some cases, hundreds of thousands of years. Some changes that are already playing out, such as warming oceans and rising sea levels, are irreversible for centuries to millennia, according to a new United Nations (UN) report. The report, made by thousands of scientists across 195 member governments, states that greenhouse gas emissions from human activities have caused global warming at a rate not seen in at least the past 2,000 years. It estimated that human-caused climate change is responsible for approximately 1.1 degrees Celsius of warming since 1850-1900, the earliest period with reliable measurements of global surface temperatures.

Alarmingly, global temperatures are expected to exceed 2 degrees Celsius of warming this century unless deep reductions in carbon dioxide and other greenhouse gas emissions occur in the coming decades. Some changes that are already playing out, such as warming oceans and rising sea levels, are irreversible for centuries to millennia, according to the report, the most comprehensive assessment from the UN’s Intergovernmental Panel on Climate Change (IPCC) since 2013. The IPCC, established in the late 1980s, consists of thousands of scientists across 195 member governments, who pore over the most recent published and peer-reviewed research on global warming and compile the findings into a report on the current state of climate. The assessment, which includes a look at the future risks and impacts of climate change, typically represents consensus within the scientific community. More than 230 authors contributed to the latest report.

Experts say it is unequivocal that human influence has warmed the atmosphere, ocean and land. No matter what humans do going forward, the future will be hotter than it is now. Climate scientists have warned that the increase in average global temperatures should be limited to under 2 degrees Celsius, or 3.6 degrees Fahrenheit, in order to avoid the most devastating effects of global warming. The 2-degree benchmark was set by climate negotiators in Copenhagen in 2009, but studies have increasingly found that the target may already be out of reach. The IPCC has been warning of the dangers of climate change for more than three decades, but the countries, especially the world’s biggest economies that are responsible for the bulk of greenhouse gas emissions, haven’t done enough to address the problems. “The world listened, but it didn’t hear. The world listened, but it didn’t act strongly enough. As a result, climate change is a problem that is here, now. Nobody is safe. And it is getting worse faster,” a UN official said.

The new assessment links human-caused climate change with increases in extreme weather events around the world. The report also details how the increasing ocean and surface temperatures will cause myriad physical changes in climate, including drought, heat waves, heavy rainfall and coastal flooding, in different regions of the planet. “It is virtually certain that hot extremes (including heat waves) have become more frequent and more intense across most land regions since the 1950s, while cold extremes (including cold waves) have become less frequent and less severe,” the authors wrote, adding that human-caused global warming is the “main driver” of those changes. Recent events, including widespread drought in the western US, heat waves across Europe and North America and devastating wildfires in Greece, Turkey and the US have highlighted the consequences of a warming world. “The climate is behaving like an athlete on steroids,” said Erich Fischer, a climate scientist at ETH Zürich and one of the authors of the IPCC assessment.

Some warming regions are projected to dry out, while others are poised to get wetter. In some instances, both can happen in the same place, the averages may not shift much, but the extremes may grow, leading to periods of drought followed by deluge. This weather whiplash wasn’t appreciated as much until recently and is yet another signal of how humans are changing the climate. The world has already warmed 1.1 degrees Celsius since the dawn of the industrial revolution. It is clear that humanity’s gargantuan output of greenhouse gases — currently about 2.6 million pounds of carbon dioxide per second — is the culprit. Without the combustion of fossil fuels, the planet would very likely be much cooler. Humans are dangerously warming the planet through activities like burning fossil fuels and clearing lands for agriculture and urban development.

According to an earlier UN report, South Asia is among the regions adversely impacted by climate change. It noted that extreme weather events had combined with Covid-19 pandemic, impacting millions of people across the globe. Pakistan is ranked among top 10 countries of the world, which were most affected by climate change in the past 20 years. It has lost 0.53pc per unit GDP, suffered economic losses worth $3.8 billion and witnessed 152 extreme weather events from 1999 to 2018. According to international estimates, it needs between $7 billion and $14 billion per year for climate adaptation. International studies point out that losses from climate change are compounding with the passage of time. Pakistan is likely to become the most adversely affected country in the South Asian region, a study by the World Climate Research Programme and the King Abdullah University of Science and Technology says. In the next 60 to 80 years, the temperature in the northern areas of Pakistan is expected to increase by six degrees. The high temperatures will have an immediate impact on glaciers. The ice will melt rapidly causing floods not only in villages but also in big cities. This may also lead to extreme climatic conditions, such as heavy rainfalls and massive droughts.

While it is depressing to think that there are so many changes that are irreversible for a long period of time, it is heartening to note that the changes can be slowed down with rapid, strong and sustained reductions in greenhouse gas emissions. The worsening climate crisis calls for practical steps to save the world and its population from its adverse effects. The rich countries will have to lead from the front because they are responsible for the problem and they have the resources to mitigate it.