The Evidence for Climate Change
- Rick Bonetti
- 2 days ago
- 8 min read
Updated: 2 hours ago
I am not a scientist, so I asked Google Gemini: "What is the evidence for climate change?"
Gemini said:
"The scientific evidence for climate change is extensive, with observations from the atmosphere, oceans, and land confirming global changes."
"There is an overwhelming scientific consensus that human activities, particularly the burning of fossil fuels, are the primary cause."
Key evidence includes:
Global Temperature Rise: Earth's average surface temperature has increased significantly, with the most substantial warming occurring since the mid-20th century.
Warming Oceans: Oceans have absorbed most of the excess heat from greenhouse gases, leading to expansion and sea level rise.
Shrinking Ice: Ice sheets and glaciers are losing mass globally, and Arctic summer sea ice has decreased considerably.
Sea Level Rise: Global sea level has risen, and the rate of increase has accelerated in recent decades, contributing to coastal risks.
Increased Greenhouse Gas Concentrations: Atmospheric concentrations of
CO2 and other greenhouse gases have risen dramatically since the Industrial Revolution, with CO2 levels at their highest in millions of years.
Extreme Weather Events: The frequency and intensity of extreme weather events such as heatwaves and floods are increasing.
Ocean Acidification: The absorption of human-produced CO2 is making ocean water more acidic, harming marine life.
Changes in Ecosystems: Alterations in plant and animal habitats and life cycles are being observed.
These observations, supported by organizations like NASA and the IPCC, demonstrate changes in the climate system that cannot be explained by natural variations alone.
Direct Observations of a Warming Planet
Global Temperature Rise: The Earth's average surface temperature has risen significantly since the late 19th century. The last decade (2015-2024) is the warmest on record, and the 10 warmest years since record-keeping began in 1880 have all occurred in the 21st century.
Warming Oceans: The ocean absorbs most of the heat from global warming, with the rate of warming increasing over the past two decades across all depths. Warmer water expands, contributing to sea level rise.
Shrinking Ice Sheets and Glaciers: Ice sheets in Greenland and Antarctica are losing mass, and glaciers are retreating on nearly every continent. This widespread melting is visually documented through repeat photography and satellite analysis.
Sea Level Rise: Global sea level has risen by approximately 8-10 inches since 1900, with the rate of rise accelerating since 1990. This is caused by both melting ice and the thermal expansion of ocean water.
Atmospheric Changes
Increased Greenhouse Gas Concentrations: Concentrations of carbon dioxide (CO2), methane, and nitrous oxide in the atmosphere have reached unprecedented levels in at least the last 800,000 years.
Unique Isotopic "Fingerprint": Scientific analysis of the atmospheric CO2 shows an isotopic signature that specifically points to the burning of ancient fossil fuels (coal, oil, and gas) as the source, rather than natural sources like volcanoes.
Changes in Natural Systems
Extreme Weather Events: Climate change is increasing the frequency and intensity of extreme weather, including heat waves, droughts, wildfires, and severe storms/flooding.
Ocean Acidification: The ocean absorbs excess CO2 from the atmosphere, which changes the water's chemistry and makes it more acidic, endangering marine life and coral reefs.
Biological Shifts: Changes in the timing of seasonal events, such as plants "leafing out" earlier in spring and shifts in the migratory patterns and geographic ranges of some species, further confirm a widespread warming trend.
"The overwhelming consensus among actively publishing climate scientists—over 99% according to recent studies—is that these climate-warming trends are a direct result of human activities."
I then asked Gemini: "What are the financial impacts of climate change in the next 10 years?"
Gemini answered:
"In the next 10 years, the financial impacts of climate change will intensify, resulting in
trillions of dollars in global economic losses, rising household costs, and significant market disruption. The costs of inaction on climate change are projected to be substantially higher than the investment needed for mitigation and adaptation."
Key Financial Impacts by 2035
Massive Economic Losses: A recent study estimates that climate change damages will cost the global economy $38 trillion annually by 2049, a trend that will accelerate over the next decade. This is projected to reduce average income per capita by 19% globally within the next 25 years.
Increased Household Costs: American households are already facing rising expenses, with some paying up to $1,000 extra per year due to climate-related issues. These costs include:
Higher Insurance Premiums: Premiums increased by about 48% between 2020 and 2024, with high-risk areas seeing the largest spikes. In some high-risk zones, insurance may become unavailable altogether, impacting property values and the housing market.
Higher Energy and Utility Bills: Warmer temperatures increase cooling costs, and utility rates are rising to cover the damage from severe storms and wildfires.
Lost Wages and Health Costs: Climate-related events like wildfire smoke and extreme heat are projected to reduce working hours and productivity, with global health costs from air pollution and climate change far exceeding $800 billion annually in the U.S. alone.
Business Disruptions and Corporate Losses: Companies that fail to adapt to escalating climate risks like extreme heat and flooding could lose up to 7% of annual earnings by 2035. Industries most vulnerable include telecommunications, utilities, and energy companies.
Infrastructure Damage: Physical risks from extreme weather events, such as hurricanes and wildfires, result in billions of dollars in property and capital loss each year. In 2024 alone, the U.S. experienced 27 weather/climate disaster events with losses exceeding $1 billion each.
Global Inequality Widening: The financial burden will not be felt equally; poorer countries and communities are disproportionately affected and have fewer resources to adapt.
Investment Opportunities and Transition Costs: The transition to a low-carbon economy presents growth potential, with green markets potentially expanding from $5 trillion to $14 trillion by 2030. However, adequate investment is needed, with climate finance needs estimated to be between $5.4 trillion and $11.7 trillion per year until 2030 to meet global climate goals."
"Overall, the financial impacts of climate change in the next decade will be significant, driven by both the increasing frequency and intensity of physical climate events and the ongoing economic and policy shifts required for a global energy transition."
Gemini sourced 18 sites, including:
Climate change may cost $38 trillion a year by 2049, study says - EPIC
Apr 19, 2024 — Climate change may cost $38 trillion a year by 2049, study says. ... EPIC Scholar Amir Jina talks on the economic impact:
The University of Chicago
The Cost of Inaction - CPI - Climate Policy Initiative
Jan 4, 2024 — In fact, inaction will be much more costly. * The two-year Global Stocktake for the Paris Agreement concluded at COP28 ...
Climate Policy Initiative
Costs of Climate Change: Financial and Economic Impacts on ...
Sep 25, 2025 — Higher temperatures due to climate change increase the total rate of inflation in the economy by 0.3-1.2 percentage po...
I then asked Gemini: "What sectors are most vulnerable to climate change by 2035?"
Gemini answered:
"By 2035, the sectors most vulnerable to climate change are those heavily reliant on stable climate conditions or which face significant regulatory and market pressures during the transition to a low-carbon economy. These include agriculture, utilities, telecommunications, energy (especially fossil fuels), construction, and transportation."
"Vulnerability stems from both physical risks (extreme weather, resource scarcity) and transition risks (new regulations, shifting markets)."
Sectors Vulnerable to Physical Risks
These sectors are directly exposed to the physical impacts of climate change, such as extreme heat, drought, flooding, and severe storms.
Agriculture and Food Supply: This sector is highly exposed to physical climate risks. Crops and livestock suffer from rising temperatures, drought, fire, and flooding, which will likely lead to reduced yields and higher food prices.
Utilities (Water and Power Generation): Utilities are vulnerable to water stress, as both thermal and hydroelectric power generation require significant, reliable water sources. Infrastructure damage from severe storms and heat also strains the grid and increases costs for consumers.
Infrastructure and Transportation: Critical infrastructure, including roads, rail lines, airports, and power grids, is at risk from sea level rise and extreme weather events. Inland waterways, like the Mississippi and the Rhine, are experiencing disruptions to freight traffic due to droughts.
Construction: Manual labor in construction becomes more dangerous in extreme heat, and projects face increased costs for redesigns, cooling retrofits, and higher insurance premiums due to flood and storm risks.
Tourism: Destinations in the Mediterranean or the Caribbean, or those reliant on winter recreation (like ski resorts), face significant disruption from extreme heat, shorter snow seasons, and intense storms, impacting local economies where tourism makes up a large part of GDP.
Telecommunications: This sector is highly exposed because essential fiber optic cables and data centers, often buried along coastlines, are vulnerable to sea level rise and flooding.
Sectors Vulnerable to Transition Risks
These sectors face significant financial vulnerability from the global shift away from fossil fuels, driven by new policies, carbon pricing, and technological innovation.
Energy (Oil, Gas, and Coal): The fossil fuel industry faces major transition risks. Increasing government regulations, carbon taxes, and the rise of renewable energy sources can lead to stranded assets (fossil fuel deposits or infrastructure that must be abandoned), causing huge financial losses for companies and their investors.
Heavy Industry/Manufacturing: Sectors like steel, cement, and chemical production are high-emitters and will be significantly impacted by carbon pricing and regulations. Companies that fail to decarbonize face mounting transition risks, including reputational damage and potential loss of market share to low-carbon alternatives.
Financial Services (Insurance and Banking): The financial sector is vulnerable to cascading risks from physical and transition impacts across all other industries. Insurers, in particular, struggle with increasingly unreliable risk models for natural disasters, which can lead to properties becoming uninsurable or prohibitively expensive."
Note: Gemini sourced 18 sites for its response above.
The President has called global warming a hoax. Several books have been written questioning the validity of concern for taking immediate actions to reduce the impact of global warming.
Author Johannes Kilian-Berger - "Publicly available information regarding the specific educational credentials of author Johannes Kilian-Berger is extremely limited. While he is identified as the author of climate-skeptic literature, such as "Die Klimawandel-Lüge: Wie man uns täglich belügt," his formal academic background and professional qualifications are not typically included in standard biographical blurbs for his works."
Author Larry Bell is a professor of space architecture at the University of Houston.
Author C. Paul Smith is a trust attorney, conservative podcaster, and devout Mormon.
Author Steven E. Koonin was a Caltech theoretical physicist for 30 years, a former government official, and he held the role of Chief Scientist at BP from 2004 to 2009.
Based on the evidence outlined above and the questionable credentials of these authors as atmospheric scientists, I personally do not think it is worth the time to engage with most climate deniers. It is more fruitful to have conversations with those two-thirds of Americans who already understand that global warming is real and is caused by human activity, but just don't know what to do.
The real "hoax" is perpetrated by those who know that spreading doubt, misinformation and lies will persuade some disengaged voters to believe them, rather than acknowledge the clear evidence, and thus not demand appropriate actions.
On December 8, 2025, PBS science correspondent Miles O’Brien and digital anchor and correspondent Deema Zein interviewed scientists, academics, digital creators, influencers, and others about the challenges they face while communicating facts about science, climate, health, and technology on a special livestreamed Reddit “Ask Me Anything” (AMA) event they called “Tipping Point – Turning Science Into Solutions.”
During this mega AMA, they shared what they’ve found that works.
Scientists, academics, digital creators, and influencers all face a critical challenge: How can science and fact-based information break through rampant misinformation, disinformation, media silos, and polarization?
Meanwhile, the New York Times reported on December 17, 2025, that "The Trump administration said it will be dismantling the National Center for Atmospheric Research in Colorado, one of the world’s leading Earth science research institutions."