Yes. Climate change is a measurable, accelerating threat backed by decades of physical evidence. Earth’s surface temperature in 2024 was 1.47°C (2.65°F) warmer than the mid-19th century average, making it the hottest year on record. That warming is driving a cascade of consequences that are already affecting human health, food systems, economies, and ecosystems worldwide.
What the Measurements Show
Carbon dioxide in the atmosphere now sits around 429 parts per million, well above the roughly 280 ppm that held steady for thousands of years before industrialization. That extra CO2 traps heat. Attribution studies from the IPCC’s most recent assessment find that greenhouse gas emissions from human activity are responsible for approximately 1.07°C of the warming observed between 1850 and 2019. Human influence is the main driver, not natural cycles or solar variation.
The warming isn’t hypothetical or gradual in a way that buys time. NASA recorded 2024’s global surface temperature at 1.28°C above the 20th-century baseline. The best current estimate for climate sensitivity (how much temperatures rise if CO2 doubles) is 3°C, narrowed from a wider range in earlier assessments. That means every decade of continued emissions locks in more warming with compounding effects.
Rising Seas and Acidifying Oceans
Sea levels rose at 0.59 centimeters per year in 2024, roughly 35% faster than the expected rate of 0.43 centimeters per year. That acceleration comes from thermal expansion of ocean water and accelerating ice loss in Greenland and Antarctica. For coastal communities, even small increases in baseline sea level magnify the reach of storm surges and high tides, turning once-rare flooding into a recurring problem.
Meanwhile, the ocean has absorbed so much CO2 that its water is now 30% more acidic than it was 200 years ago. Ocean pH has dropped from 8.2 to 8.1 since the industrial revolution, a shift faster than any known change in ocean chemistry in the last 50 million years. That matters because shellfish, coral reefs, and the tiny organisms at the base of the marine food web all depend on stable water chemistry to build their shells and skeletons. If emissions continue on their current path, pH could drop another 0.3 to 0.4 units by 2100, pushing many marine ecosystems past their ability to adapt.
Heat-Related Deaths Are Climbing
Extreme heat is the most direct way climate change kills people. Projections from systematic reviews of heat-mortality research show heat-related deaths could more than double by the 2050s and triple by the 2080s compared to 1990s levels. Even under optimistic scenarios that assume people gradually acclimatize to hotter conditions, mortality from heat increases by 70% or more by mid-century.
Those numbers aren’t evenly distributed. Some countries face projected increases of 100% to 1,000% in excess deaths from heat by the 2090s. Cities with large elderly populations and dense concrete infrastructure (which holds heat overnight) are especially vulnerable. In the New York City metropolitan area alone, projections show a 47% to 95% increase in heat-related deaths by the 2050s.
Infectious Diseases Are Spreading to New Areas
Warmer temperatures are expanding the geographic range of mosquitoes, ticks, and the diseases they carry. Dengue fever has seen a 30-fold increase in global incidence over the past 50 years, with an estimated 100 to 390 million infections each year. Malaria-causing parasites are showing up more frequently in tropical highland regions across East Africa, Nepal, and Colombia, areas that were previously too cool for transmission. Infection risk in East Africa is expected to rise by 20% over the next 20 to 50 years.
In temperate regions, Lyme disease tells a similar story. Cases in Europe climbed from about 3,000 in the early 1990s to 35,000 by the late 2000s. In the United States, Lyme disease now affects roughly 300,000 Americans each year. Simulations show that even if warming is held to 1.5°C (the Paris Agreement target), Lyme-carrying ticks will continue spreading farther north into parts of Canada that have never dealt with the disease.
Wildfires and Extreme Weather
Climate change has doubled the number of large wildfires in the western United States between 1984 and 2015. The mechanism is straightforward: higher temperatures dry out vegetation faster, creating more fuel. Warming accounted for more than half the observed decrease in fuel moisture across western forests from 1979 to 2015, and the burned area doubled over roughly the same period. Fire seasons are starting earlier and lasting longer, putting more people and property in harm’s way.
The economic toll from extreme weather reflects this trend. U.S. billion-dollar weather and climate disasters cost a combined $746.7 billion over the five years from 2020 to 2024, averaging $149.3 billion per year. That includes hurricanes, floods, droughts, and wildfires, categories where frequency and intensity are increasingly influenced by a warmer atmosphere holding more moisture and energy.
Why Half a Degree Matters
One of the clearest findings from climate science is that the difference between 1.5°C and 2°C of total warming is not a minor rounding error. At 2°C, coastal flooding risks, freshwater stress, and marine ecosystem damage all increase substantially compared to 1.5°C. Holding warming to 1.5°C would prevent the thawing of an estimated 1.5 to 2.5 million square kilometers of permafrost, an area roughly three to five times the size of France. Permafrost thaw releases stored methane and CO2, which in turn accelerates warming further.
At 2°C, adaptation options narrow. Coral reefs face near-total loss. Water scarcity intensifies in already dry regions. The window for communities to adjust shrinks because changes arrive faster and hit harder. Every fraction of a degree of warming avoided preserves more options for the future.
The Bottom Line on Evidence
The question of whether climate change is a real threat isn’t a matter of opinion or political framing. It’s answered by thermometers, tide gauges, atmospheric chemistry, hospital records, and insurance claims. Global temperatures are at their highest point in recorded history. Oceans are rising faster than expected. Heat deaths are increasing. Disease-carrying insects are colonizing new territory. Wildfires are burning more land. And the economic costs are running into the hundreds of billions of dollars per year in the United States alone. The evidence is not ambiguous, and the trajectory gets worse with every year of inaction.