Quick Answer
A single supercontinent would create enormous continental interiors far from the moderating influence of the ocean. Coastal climates would remain relatively maritime, while the interior could become much more seasonal and arid. Ocean circulation and monsoon patterns would also change, so the exact climate would depend on the continent's latitude and shape.
The interior would be the biggest problem
Today, oceans moderate temperatures across much of the planet. A huge continuous landmass would place an enormous area hundreds or thousands of kilometers from the nearest coast. Rainfall would decline toward the interior in many configurations, producing strong continental climates.
Coastlines become ecological highways
The edge of the supercontinent would contain most marine influence. Rivers would drain toward a smaller number of major basins, while coastal ecosystems would stretch along an immense continuous shoreline.
Oceans would circulate differently
Continents act as barriers that steer ocean currents. A single landmass would remove many of those barriers and open or close ocean gateways. That could redistribute heat between the tropics and high latitudes and alter regional climate dramatically.
Evolution would follow new geography
A giant continent would connect habitats that are currently isolated by oceans while separating other populations by enormous dry interiors. Some animals and plants could spread across previously separate regions, while interior deserts would create new barriers.
SpeculativeThe exact climate of a supercontinent cannot be summarized by one simple prediction. Latitude, mountain ranges, ocean gateways and atmospheric circulation would all matter.
Humans would have a different map
If such a configuration existed today, international transport would be dominated by land routes across the interior and maritime routes around the perimeter. Political boundaries and economic centers would likely cluster around rivers, mountain passes and coastal corridors.
The bottom line
One continent would not produce one uniform climate. It would amplify the contrast between maritime coasts and continental interiors while reorganizing ocean currents and biological connections across the planet.
A single supercontinent would not simply redraw coastlines. Continental position changes ocean circulation, atmospheric transport and the distribution of land versus sea, so climate patterns would also change. Geological processes would continue to reshape the continent over millions of years, and the exact climate outcome would depend strongly on where the landmass sat and how high its interior was.
Why the map would matter
A note on our approach: Every article on WhatIfLab separates what current science establishes from what remains genuinely speculative. Where we cite a figure or finding, it reflects published, mainstream research at the time of writing — not a prediction dressed up as fact.