The Science: A Warming Planet and Its Thresholds

According to the Intergovernmental Panel on Climate Change (IPCC), Earth’s average surface temperature has already increased by about 1.2°C above pre-industrial levels. This rise is driven by the accumulation of greenhouse gases such as carbon dioxide (CO₂), methane (CH₄), and nitrous oxide (N₂O), mostly from burning fossil fuels, agriculture, deforestation, and industrial processes.

The 1.5°C threshold, set in the 2015 Paris Agreement, is more than symbolic. It marks a limit beyond which scientists expect the risk of severe, often irreversible impacts to increase dramatically.

What’s Already Happening: The Human Toll

1. Hunger and Food Insecurity

Global warming disrupts agriculture by increasing droughts, floods, and extreme heat. The World Food Programme warns that up to 783 million people face chronic hunger — a number that is rising, partly due to climate shocks. For example:

• Droughts in the Horn of Africa have caused crop failures and livestock deaths, pushing millions toward famine.

• Heatwaves in India and Pakistan are reducing wheat yields in one of the world’s key breadbaskets.

• Changing rainfall patterns threaten rice and maize production in Southeast Asia and sub-Saharan Africa.

2. Migration and Displacement

The World Bank projects that climate change could force more than 216 million people to migrate within their own countries by 2050, driven by desertification, sea level rise, and lack of water.

• Island nations like Kiribati and the Maldives face existential threats from rising seas.

• In Central America’s “Dry Corridor”, crop failure is pushing thousands northward, fueling migration to the U.S.

• Urban centers in the Global South are already seeing rapid influxes of climate refugees, straining infrastructure and services.

3. Conflict and Instability

Climate stress can act as a threat multiplier, increasing the likelihood of conflict in fragile states:

• The Syrian civil war was preceded by the country’s worst drought on record, contributing to mass rural-urban migration and social unrest.

• Water scarcity in the Sahel region has intensified resource-based conflicts between farmers and herders.

• Climate-induced displacement can inflame ethnic, political, and economic tensions in host regions.

4. Water Scarcity

Over 2 billion people already live in water-stressed regions. As glaciers retreat and rainfall patterns change, water access becomes more fragile:

• The Andes, Himalayas, and Alps are losing glacial mass, threatening freshwater supplies for hundreds of millions.

• Rivers like the Nile, Indus, and Colorado are overdrawn and increasingly unreliable.

• Rising temperatures also increase evaporation and reduce snowpack, further depleting water sources.

What If We Don’t Act? The Scenarios Ahead

If the world continues on a “business-as-usual” trajectory — projected to exceed 2.7°C by the end of the century — the consequences will be profound:

• Widespread coral reef collapse, endangering marine biodiversity and coastal livelihoods.

• Permafrost thaw in the Arctic, releasing vast amounts of methane — a powerful greenhouse gas — accelerating warming.

• Extreme heatwaves becoming annual occurrences, threatening public health and productivity.

• Loss of biodiversity, with up to one million species at risk of extinction.

• Sea levels could rise by over 1 meter by 2100, threatening megacities like New York, Jakarta, and Lagos.

The World Meteorological Organization warns that each fraction of a degree counts — a 2°C world is significantly more dangerous than a 1.5°C world.