What is our climate future?
Code Red for Humanity
Written by Lan Richart
Co-Director, Eco-Justice Collaborative
Climate Change
Climate change is the long-term shift in average temperature, precipitation, humidity, and wind patterns for a given geographic area. Scientists have confirmed that global climate patterns are changing, primarily as a result of human activities. The principal driver of climate change is the accumulation of greenhouse gases in the earth’s atmosphere.
For thousands of years, the earth’s climate remained stable, as water vapor and other gases served to retain some of the sun’s infrared radiation, like a greenhouse, keeping the planet’s temperature within a range that supported humans and other species. With the onset of the industrial age, the burning of carbon rich fuels such as coal, oil and natural gas released increasingly vast amounts of carbon dioxide into the atmosphere. Farming and natural gas extraction have released additional amounts of other greenhouse gases, such as nitrous oxide and methane. As a result, today’s carbon dioxide levels are 50% higher than pre-industrial times, and global climate and associated weather patterns are rapidly changing. These changes have potentially dire consequences.
Where are we now?
For nearly 6,000 years, the carbon dioxide levels in the earth’s atmosphere remained around 280 parts per million. In December of 2024, carbon dioxide concentrations, as measured by the National Aeronautics and Space Administration , were 425 parts per million, and climbing.
Based on a multi-decade period used to define average global temperature, the earth’s temperature has risen 1.28° Celsius above pre-industrial levels. However, in 2024, the earth’s average surface temperature reached the highest point ever recorded, with levels at 1.47° Celsius, or 2.65° Fahrenheit, above the pre-industrial average. With the last ten years being the hottest in recorded history, indications are that crossing the 1.5° Celsius threshold is not just likely. It is imminent.
The Challenge ahead
The international Panel on Climate Change (IPCC), representing 195 countries and many hundreds of scientists from around the world, has agreed that to prevent worsening and potentially irreversible effects of climate change, the global average temperature should not be allowed to exceed that of pre-industrial times by more than 1.5° Celsius (2.7° Fahrenheit). In its 2023 AR6 Synthesis Report, the IPCC states that, based on current emission rates, the 1.5° Celsius level is likely to be reached between 2030 and 2035. Under a moderate emissions scenario, studies project the world will pass the 2.0° Celsius threshold by mid-century.
All global pathways that will limit warming to 1.5° Celsius with no or limited overshoot, as well as those that limit warming to 2° Celsius, involve deep and immediate reductions in greenhouse gas emissions.
What does a 1.5°C world look like?
Limiting global warming to 1.5°C or less will significantly mitigate the risks, adverse impacts, and related losses and damages from climate change. Failing to do so will result in more frequent and severe extreme weather events, such as heatwaves, droughts, wildfires, and heavy precipitation leading to flooding. Exceeding 1.5° Celsius also could trigger multiple irreversible and dangerous climate tipping points, including the breakdown of major ocean circulation systems, abrupt thawing of boreal permafrost, and the collapse of tropical coral reef systems. Even if global warming is limited to 1.5° Celsius above pre-industrial levels, the impacts will be significant.
What does a 2.0°C world look like?
A 2.0° Celsius rise in global temperature would lead to a more extreme climate, with heightened frequency and intensity of heatwaves, more frequent and severe droughts, rising sea levels, potential widespread crop failures, mass coral bleaching, and disruption of ecosystems. These climate impacts would affect many regions globally, particularly those near the equator.
NASA researchers determined that more than 25% of the global population could experience an extra month of severe heat stress annually, compared to the mid-20th century. Additionally, the combination of high temperatures and drought could increase the risk of devastating wildfires. Financial losses would be heavy.
What does a world of 2.7°C look like?
This is a world of dramatic storm events, sustained droughts, water scarcity, flooding, and sea level rises. These dramatic changes would displace coastal communities and result in massive financial costs for climate damage and mitigation. There is a high probability of reaching climate tipping points, such as altering the Atlantic Meridional Ocean Current (AMOC) and the collapse of ocean and terrestrial ecosystems, as well as accelerating methane releases. Mass relocation of climate refugees would strain public resources, and international conflicts would increase due to resource wars.
What is our climate future if we change nothing?
Under current policies, there is a reasonable probability that global warming could reach 3° Celsius by the end of this century. However, emissions are not yet expected to achieve net-zero levels — a state where greenhouse gases going into the atmosphere are counterbalanced by removing equivalent amounts from the atmosphere — by 2100. So, temperatures would continue to rise beyond that point. On our current course, we, and the planet on which we live, will face irreversible changes, leading to costly and catastrophic consequences for humanity.
Denial and delay are not in our best interest
The choices we make right now are determining the kind of world we will live in, and most certainly the kind of world our children and future generations will inherit. We already have the tools needed to make immediate and dramatic cuts in greenhouse gas emissions. However, successfully responding to the climate crisis will require an all-out effort, rethinking the way we live and the way we use energy in all sectors of society. Technological solutions will abound, but will not in and of themselves provide the responses needed to address the challenges ahead. In many cases, these technological advances will be driven not by their climate effectiveness, but by their financial profitability. We cannot count on technology alone to solve our climate crisis.
The planet's future － OUR future － is in our hands.
