1.5 Degrees of Global Warming—Are We There Yet?

Since climate change emerged as a global concern in the 1970s, scientists have been trying to predict the impacts of varying amounts of temperature rise. By 1990, when the United Nations’ Intergovernmental Panel on Climate Change (IPCC) published its first assessment, the authors defined the increase of global average temperatures by 2 degrees Celsius (compared to preindustrial levels) as “an upper limit beyond which the risks of grave damage to ecosystems, and of nonlinear responses, are expected to increase rapidly.” 

Those “nonlinear responses” refer to the triggering of irreversible tipping points—such as rapid glacier melt, collapsing coral reefs, and thawing permafrost. Once past a certain threshold, such events build upon themselves, exponentially exacerbating the effects of climate change. In short, hitting a tipping point should be avoided at all costs, as it would bring devastating losses to ecosystems, societies, and human lives. 

It’s important to note, however, that even before reaching tipping point status, climate change causes massive amounts of damage. Acknowledging this fact in the late aughts, many small island nations and other countries on the climate frontlines banded together to demand “1.5 to stay alive.” At the 2009 climate talks in Copenhagen, Archbishop Desmond Tutu said, “A global goal of about 2 degrees Celsius is to condemn Africa to incineration” while Sudanese diplomat Lumumba Di-Aping, then chairman of G-77, a group of now 134 low-income nations, called it “a suicide pact.” 

After much deliberation, the Paris Agreement of 2015 codified the 1.5 degree goal for the first time in international climate policy. In its text, 196 countries pledged to cut their carbon emissions in order to limit global average temperature rise to “well below” 2 degrees while they pursue efforts to limit it to 1.5 degrees. 

Examples of extreme and “unnatural” weather fueled by climate change abound. In the past year alone—in which we’ve hit 1.4 degrees of warming—Europe emerged from what researchers called its worst heat wave on record, a glacial collapse and subsequent monstrous flood in Nepal and Tibet killed thousands, and wildfires tore through large swaths of the United States and Canada. The climate crisis is very much already here, but that is certainly not our cue to give up. Every bit of warming prevented is worth the effort.

The IPCC released a special report in 2018 that compared the potential consequences between the warming of the climate by 1.5 degrees versus 2 degrees. Warming by that extra half degree, the report found, could subject up to 420 million more people to frequent exposures to extreme heat waves and up to 10.4 million to the impacts of sea level rise. It could also significantly raise the probability of sea ice–free summers in the Arctic, lead to an additional 700,000 square miles of permafrost thawing, and increase crop failures in critical agricultural areas of sub-Saharan Africa, Southeast Asia, and Central and South America.

And that half degree of warming would not look the same everywhere. Over the past 40 years, the Arctic has been heating up about four times faster than the rest of the world, and Europe appears to be the fastest-warming continent. The effects of climate change are not uniform, but what happens in one place can have cascading effects elsewhere. The melting of polar ice sheets, for instance, affects sea level rise elsewhere. Rising seas are already destroying the coastlines and freshwater supplies of many low-lying small island nations in the Pacific Ocean, some of which could soon become uninhabitable or even disappear completely under the waves.

There’s no doubt that climate change is taking a heavier toll on low-income countries, particularly in the Global South. But wealthier countries, many of which are responsible for disproportionate amounts of historic greenhouse gas emissions, are also face-to-face with the climate emergency. Intensifying wildfires, droughts, floods, hurricanes, storm surges, algal blooms, invasive species, vector-borne diseases, crop failures, economic hardships—the effects of present-day global warming are bad enough and will only worsen with increased temperature rise.

Yes and no—it’s complicated. In the 2026 overshoot report, the UNEP estimates that the expected peak temperature rise, under the best-case scenario, will be between 1.6 and 1.8 degrees. It also states that observed global temperatures have been increasing at about a quarter of a degree per decade, with some recent studies showing that rate being even higher. “Extrapolating current trends, global warming may reach 1.5°C around the end of this decade,” conclude the UNEP authors. 

Because temperatures naturally fluctuate year to year, the IPCC doesn’t just look at the most recent data to make its assessment. Instead, it calculates average temperatures over the past 20 years. While this method ensures a better scientific picture of climate patterns over time, the world doesn’t have the luxury of waiting an extra decade or two to run the numbers before taking preventative action. 

Some climate scientists therefore suggest a new approach, one that would look at temperatures over just the past 10 years plus the projected temperatures for the next decade and then take an average. This would allow policymakers to more quickly assess whether their current emissions-fighting efforts are up to snuff. 

Back in 2012, a landmark World Bank study suggested that the atmosphere was on a path to a whopping 4 degrees of warming—needless to say, a scenario that would have devastating consequences for all of humanity. A little over a decade later, the UNEP estimated that updated national climate commitments have put us on track for 2 to 3 degrees of warming. While this would be a vast improvement over 4 degrees, it’s still sorely outside the range of the Paris Agreement goals. In addition, the U.N. calculation is based on the assumption that all of the countries would fulfill their commitments—perhaps a bit optimistic, given that there are no penalties within the Paris Agreement for countries that fall short of their pledges. 

Last year, ahead of COP30 in Belém, Brazil, U.N. Secretary-General António Guterres issued a warning, stating that “a temporary overshoot beyond the 1.5 degrees Celsius limit—starting at the latest in the early 2030s—is inevitable,” according to science. And with the awareness of the growing threats, many of the countries present at the negotiations did step up their commitments to keeping that goal in reach, albeit much more action will be needed.

Much more money too. The UNEP report urges transformational adaptation and makes it clear that we won’t achieve it without significant public and private investments. Specifically, in its Adaptation Gap Report 2025, it pegged adaptation finance needs in developing countries at up to $365 billion per year by 2035, more than 10 times what we saw in 2024, when international adaptation finance flows from developed countries reached just $35 billion.

To help people become more resilient to climate change requires “investment in economic stability, public health, food security, water security, and human dignity, not as a secondary environmental issue,” writes NRDC’s senior director for climate adaptation Dr. Adelle Thomas. Thomas stresses that leaders must make the Paris Agreement’s global goal on adaptation a priority at the upcoming COP31 in Antalya, Türkiye. Countries will need to decide how to measure progress and speed up implementation accordingly.

As local needs emerge—for example, many communities will be forced to relocate within their home countries as sea levels inundate coastal areas, crops fail to grow, or other climate impacts worsen—they’ll require support in real time. And support for such losses and damages must become a core pillar of climate action, alongside emissions mitigation and adaptation, Thomas adds.

We must also consider the unprecedented nature of the climate crisis, which means there is still a lot that scientists just don’t know. Spikes in land and sea temperatures in 2023 greatly exceeded predictions by climate models, revealing the gaps that remain in our overall understanding of how rising temperatures could affect the complicated systems and feedback loops that govern life as we know it on this planet.

Limiting the damage and destruction from climate change will require us to minimize the magnitude and duration of overshooting the 1.5 degree limit by bringing temperatures back down as quickly as possible. Dr. Jennifer DiStefano, director of technology and innovation on NRDC’s climate and energy team, points out that this necessitates embracing new tools. 

“Addressing overshoot first and foremost requires drastic cuts in emissions but also wide-scale implementation of responsible carbon dioxide removal solutions, many of which are in early-stage development,” she says. “We have a critical window to responsibly shape those technologies and lay out a path for their sustainable growth.” NRDC recently released a new set of principles that aim to do just that.

Additionally, NRDC is supporting careful research and governance of solar radiation management. This includes strategies to induce global cooling effects, such as by injecting particles or gases in the upper atmosphere that reflect sunlight or adding reflective cloud cover in the lower atmosphere, all ideas that are being examined by the National Academies of Sciences, Engineering, and Medicine. When it comes to interventions with potentially planetary-scale impacts, including implications for the most vulnerable countries and communities, we need to clearly understand the potential risks, benefits, and governance required. Related research must be conducted responsibly and in service of public interest—and experts caution that progress on this front cannot become an excuse to slow down the work of cutting climate pollution. 

Hitting 1.5 degrees of warming isn’t like flipping a switch to climate chaos. Every tenth or hundredth of a degree of warming that we prevent will make a difference—saving countless lives, keeping vital ecosystems functioning, preventing extinctions, and ensuring our ability to grow the food we need. For many frontline communities, each small increment of warming avoided could mean the difference between a lifetime of displacement and the ability to adapt, remain rooted at home, and keep cultural traditions alive. 

While temperature targets are important in gauging our success (or lack thereof), the debate over which degree is safest or most feasible should not distract countries, companies, and other polluters from doing everything they can to minimize the duration and severity of overshooting the 1.5 degrees limit.

We know what we need to do. First, we must aggressively cut emissions by 2030 to put us on track for reaching net zero emissions by around 2050. The good news is that we already have the road map to get there. It involves expanding clean energy; modernizing the power grid; accelerating vehicle and building electrification; greening heavy industry; cutting super pollutants like methane emissions from oil and gas, agriculture, and landfills; ending deforestation and degradation; and restoring ecosystems that help absorb carbon as well as buffer storms. Second, we must expand the climate tool kit to develop and scale carbon dioxide removal and other emerging technologies. Third, we must prepare for the shifting weather patterns we know are coming to minimize the harm they will cause. Finally, we must take care of the millions of people who will bear the brunt of extreme weather, sea level rise, political instability, and the climate anxiety and grief that follow.

Would the world be better off if we had rapidly cut our climate pollution years ago or last month or even yesterday? Absolutely, but taking stronger action today is the best—and really, only—option we’ve got.