NASA, the UN, and WMO Break Down the Science: What Exactly Is Climate Change?

Climate change, primarily driven by human activity, has become one of the greatest threats to ecosystems and human life. From international bodies like the United Nations and NASA to global NGOs and private sector leaders, efforts are intensifying to reduce emissions, adapt to changing conditions, and build resilience.

The United Nations defines climate change as long-term alterations in global temperatures and weather patterns. While such shifts can occur naturally—through volcanic eruptions, variations in solar activity, or ocean cycles—scientists are united in their conclusion that, since the Industrial Revolution, human activity has been the overwhelming driver. Energy, industry, transport, agriculture, and land use together account for the majority of greenhouse gas emissions.

The UN states that: “Burning fossil fuels releases GHGs like carbon dioxide and methane which then trap heat in the Earth’s atmosphere, acting like a blanket and causing temperatures to rise.” 

Other contributors include deforestation, agriculture, and industrial operations. 

“Trees are known for their capacity to absorb carbon dioxide through photosynthesis,” says Earth.org. 

“Healthy forests act as extremely valuable carbon sinks, absorbing an estimated 16 billion tonnes of CO₂ per year and currently holding 861 gigatonnes of carbon in their branches, leaves, roots, and soils.

“Deforestation is turning these sinks into huge net emitters, threatening global climate action and contributing to a steep rise in global temperatures.”

Together, energy, industry, transport, agriculture, and land use account for the bulk of global emissions.

Monitoring climate change is a vast and complex task. NASA and the World Meteorological Organization gather data through satellites, ground stations, and atmospheric measurements. They track telltale indicators such as rising land and ocean temperatures, the steady retreat of glaciers, the thinning of polar ice sheets, and the relentless rise in sea levels. Equally worrying is the increase in extreme weather: hurricanes, floods, wildfires, heatwaves, and prolonged droughts are all becoming more intense and frequent.

Although the terms are often used interchangeably, NASA makes a distinction between “global warming” and “climate change.” Global warming refers only to the rise in Earth’s average surface temperature, whereas climate change encompasses the broader shifts in rainfall, storm intensity, and ocean circulation patterns that accompany it.

The urgency of the crisis has led to the signing of landmark international agreements. The Paris Agreement of 2015, signed by nearly every country, committed the world to limiting the temperature rise to well below 2 degrees Celsius and striving for a 1.5-degree cap relative to pre-industrial levels. The Sustainable Development Goals adopted by the UN also include Goal 13, which directly calls for urgent action on climate change. Underpinning these efforts is the UN Framework Convention on Climate Change, which provides the legal and diplomatic foundation for global cooperation.

The Intergovernmental Panel on Climate Change has warned that to avoid the most catastrophic outcomes, global emissions must be halved by 2030 and brought to net zero by mid-century.

“Having the right policies, infrastructure and technology in place to enable changes to our lifestyles and behaviour can result in a 40-70% reduction in greenhouse gas emissions by 2050,” says Priyadarshi Shukla, IPCC Working Group III Co-Chair.

“This offers significant untapped potential. 

“The evidence also shows that these lifestyle changes can improve our health and wellbeing.”

The UN plays a central coordinating role, not only through climate summits but also through the UN Environment Programme, which provides the science and diplomatic frameworks that guide policy worldwide.

UNEP states, “We tackle the climate crisis on a variety of fronts:

• Encouraging the transition to low- and zero-carbon emissions in key sectors such as energy, agriculture, buildings, forestry, industry, and transport

• Working with governments, civil society, and the private sector to improve air quality and reduce emissions of short-lived climate pollutants

• Protecting and restoring natural ecosystems such as forests, coral reefs, and peatlands while combating the sources of degradation

• Empowering communities to adapt to changing conditions by building resilient ecological foundations

• Supporting public engagement and behaviour change through global campaigns and education programmes.”

NASA contributes to understanding long-term changes, such as sea level rise, through its advanced climate models and Earth-observing satellites, generating the data needed to project future risks. The IPCC delivers authoritative scientific assessments that shape government strategies, with its 2018 report underscoring the enormous difference between limiting warming to 1.5 degrees versus two.

The UK’s Met Office also plays a pivotal role, providing climate science and modelling that help governments and industries prepare for the risks ahead.

Non-governmental organisations have long been at the forefront. WaterAid works to strengthen communities threatened by water scarcity. WWF advocates for protecting biodiversity and ecosystems under climate stress, while Greenpeace campaigns vigorously for a rapid phase-out of fossil fuels and a faster transition to renewable energy sources.

Businesses, too, are reevaluating their strategies in light of climate goals. Microsoft and Google have pledged to go beyond neutrality by becoming carbon negative. Ørsted, once reliant on fossil fuels, has transformed itself into a global leader in offshore wind. Tesla continues to push for decarbonization in transportation with its electric vehicles and energy storage systems.

The message is clear: climate change is not a distant or abstract concern. It is happening now, and it is accelerating. Only a coordinated effort across governments, industries, and civil society will be sufficient to meet the challenge.