The climate change we caused is here for at least 50,000 years and probably far longer
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Leicester (UK) (The Conversation): In February 2000, Paul Crutzen rose to speak at the International Geosphere-Biosphere Programme in Mexico. And when he spoke, people took notice. He was then one of the world's most cited scientists, a Nobel laureate working on huge-scale problems the ozone hole, the effects of a nuclear winter.
So little wonder that a word he improvised took hold and spread widely: this was the Anthropocene, a proposed new geological epoch, representing an Earth transformed by the effects of industrialised humanity.
The idea of an entirely new and human-created geological epoch is a sobering scenario as context for the current UN climate summit, COP28. The impact of decisions made at these and other similar conferences will be felt not just beyond our own lives and those of our children, but perhaps beyond the life of human society as we know it.
The Anthropocene is now in wide currency, but when Crutzen first spoke this was still a novel suggestion. In support of his new brain-child, Crutzen cited many planetary symptoms: enormous deforestation, the mushrooming of dams across the world's large rivers, overfishing, a planet's nitrogen cycle overwhelmed by fertiliser use, the rapid rise in greenhouse gases.
As for climate change itself, well, the warning bells were ringing, certainly. Global mean surface temperatures had risen by about half a degree since the mid-20th century. But, they were still within the norm for an interglacial phase of the ice ages. Among many emerging problems, climate seemed one for the future.
A little more than two decades on, the future has arrived. By 2022, global temperature had climbed another half a degree, the past nine years being the hottest since records began. And 2023 has seen climate records being not just broken, but smashed.
By September there had already been 38 days when global average temperatures exceeded pre-industrial ones by 1.5 C, the safe limit of warming set by the UN Convention on Climate Change (UNFCCC) in the Paris agreement. In previous years that was rare, and before 2000 this milestone had never been recorded.
With this leap in temperatures came record-breaking heatwaves, wildfires and floods, exacerbated by other local human actions. Climate has moved centre stage on an Anthropocene Earth.
Why this surge in temperatures? In part, it's been the inexorable rise in greenhouse gases, as fossil fuels continue to dominate human energy use. When Crutzen spoke in Mexico, atmospheric carbon dioxide levels were about 370 parts per million (ppm), already up from the pre-industrial 280 ppm. They're now around 420 ppm, and climbing by some 2 ppm per year.
In part, the warming results from cleaner skies in the past few years, both on land and at sea, thanks to new regulations phasing out old power stations and dirty sulphur-rich fuels. As the industrial haze clears, more of the sun's energy makes it through the atmosphere and onto land, and the full force of global warming kicks in.
In part, our planet's heat-reflecting mirrors are shrinking, as sea ice melts away, initially in the Arctic, and in the last two years, precipitously, around Antarctica too. And climate feedbacks seem to be taking effect, too. A new, sharp rise in atmospheric methane a far more potent greenhouse gas than carbon dioxide since 2006 seems to be sourced from an increase in rotting vegetation in tropical wetlands in a warming world.
This latest warming step has already taken the Earth into levels of climate warmth not experienced for some 120,000 years, into those of the last interglacial phase, a little warmer than the current one. There is yet more warming in the pipeline over coming centuries, as various feedbacks take effect.
A recent study on the effects of this warming on Antarctica's ice suggests that "policymakers should be prepared for several metres of sea-level rise over the coming centuries" as the pulse of warmth spreads through the oceans to undermine the great polar ice-sheets.
This remains the case even in the most optimistic scenario where carbon dioxide emissions are reduced quickly. But emissions continue to rise steeply, to deepen the climate impact.
Controls have been overridden
To see how this might play out on a geological timescale, we need to look through the lens of the Anthropocene. A delicately balanced planetary machinery of regular, multi-millennial variations in the Earth's spin and orbit has tightly controlled patterns of warm and cold for millions of years.
Now, suddenly, this control machinery has been overridden by a trillion tons of carbon dioxide injected into the atmosphere in little more than a century.
Modelling the effects of this pulse through the Earth System shows that this new, suddenly disrupted, climate pattern is here for at least 50,000 years and probably far longer. It's a large part of the way our planet has changed fundamentally and irreversibly, to become comparable to some of the great climate change events in deep Earth history.
So will this particular COP meeting, with fossil fuel interests so strongly represented, make a difference? The bottom line is that attaining, and stabilising carbon emissions at "net zero" is only a crucial first step.
To retrieve the kind of climate optimal for humanity, and for life as a whole to thrive, negative emissions are needed, to take carbon out of the atmosphere and ocean system and put it back underground. For future generations, there is much at stake.
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Texas halts H-1B visas at state universities, agencies; to affect Indians
Houston (US) (PTI): Texas Governor Greg Abbott has ordered state agencies and public universities to immediately halt new H-1B visa petitions, tightening hiring rules at taxpayer-funded institutions, a step likely to impact Indian professionals.
The freeze will remain in effect through May 2027.
The directive issued on Tuesday said that the state agencies and public universities must stop filing new petitions unless they receive written approval from the Texas Workforce Commission.
The governor's order, in a red state that is home to thousands of H-1B visa holders, comes as the Trump administration has initiated steps to reshape the visa programme.
“In light of recent reports of abuse in the federal H-1B visa programme, and amid the federal government’s ongoing review of that programme to ensure American jobs are going to American workers, I am directing all state agencies to immediately freeze new H-1B visa petitions as outlined in this letter,” Abbot said.
Institutions must also report on H-1B usage, including numbers, job roles, countries of origin, and visa expiry dates, the letter said.
US President Donald Trump on September 19 last year signed a proclamation ‘Restriction on entry of certain non-immigrant workers’ that restricted the entry into the US of those workers whose H-1B petitions are not accompanied or supplemented by a payment of USD 1,00,000.
The H1-B visa fee of USD 1,00,000 would be applicable only to new applicants, i.e. all new H-1B visa petitions submitted after September 21, including those for the FY2026 lottery.
Indians make up an estimated 71 per cent of all approved H-1B applications in recent years, according to US Citizenship and Immigration Services (USCIS), with China in the second spot. The major fields include technology, engineering, medicine, and research.
Tata Consultancy Services (TCS) is the second-highest beneficiary with 5,505 approved H-1B visas in 2025, after Amazon (10,044 workers on H-1B visas), according to the USCIS. Other top beneficiaries include Microsoft (5,189), Meta (5,123), Apple (4,202), Google (4,181), Deloitte (2,353), Infosys (2,004), Wipro (1,523) and Tech Mahindra Americas (951).
Texas public universities employ hundreds of foreign faculty and researchers, many from India, across engineering, healthcare, and technology fields.
Date from Open Doors -- a comprehensive information resource on international students and scholars studying or teaching at higher education institutions in the US -- for 2022-2023 showed 2,70,000 students from India embarked on graduate and undergraduate degrees in US universities, accounting for 25 per cent of the international student population in the US and 1.5 per cent of the total student population.
Indian students infuse roughly USD 10 billion annually into universities and related businesses across the country through tuition and other expenses – while also creating around 93,000 jobs, according to the Open Doors data.
Analysts warn the freeze could slow recruitment of highly skilled professionals, affecting academic research and innovation.
Supporters say the directive protects local jobs, while critics caution it could weaken Texas’ competitiveness in higher education and research.
The order comes amid broader debate in the US over skilled immigration and state-level interventions in federal programmes.
H-1B visas allow US companies to hire technically-skilled professionals that are not easily available in America. Initially granted for three years, these can be extended for another three years.
In September 2025, Trump had also signed an executive order ‘The Gold Card’, aimed at setting up a new visa pathway for those committed to supporting the United States; with individuals who can pay USD 1 million to the US Treasury, or USD 2 million if a corporation is sponsoring them, to get access to expedited visa treatment and a path to a Green Card.
