What are natural things that can cause global climate change and global warming?

Answer 1

Global warming is partly a natural phenomenon. In fact without this, the world would be some thirty degrees Celsius colder than it is today. Carbon dioxide is a naturally occurring greenhouse gas. At normal concentrations, it, along with other greenhouse gases, helps maintain global temperatures at a level that is comfortable for humans and other animals that have adapted to the present climate. This is the natural part of global warming.

Volcanic eruptions also add some carbon dioxide to the atmosphere, but with such infrequency that the ocean, in the absence of any additional carbon dioxide resulting from human activity, could gradually absorb this carbon dioxide and thereby maintain the long-term average concentration of atmospheric carbon dioxide within the normal range of 260 to 280 parts per million.

The Milankovich cycle, caused by subtle shifts in our planet's orbit around the Sun, can trigger a change in temperatures, but is too slight to explain the Ice Ages that the earth experiences every few thousand years. Following a Milankovich shift, there is a slight change in temperature followed over a period of many centuries by a gradual change in carbon dioxide concentrations. It is this change in carbon dioxide levels that eventually results in the Ice Ages and the subsequent warming. Of course, this is much too gradual a process to explain the present quite rapid increase in average global temperatures, and it has always been associated with Ice Ages, not with temperatures above the long-term average.

Answer 2

The earth's natural cycles has caused warming - cooling - warming - cooling cycles since the earth was young. Some think these cycles are connected to the 11-year solar spots cycle of the Sun.

El Nino / El Nina cycles of warm and cool ocean currents coming from lower South Africa to Alaska affect mini-climate changes.

There are at least 7 different warm/cool ocean currents that affect mini-climate changes, including the Pacific Decadal (every 10 years) Oscillation and the North Atlantic Oscillation which melted some of the Arctic in the past decade . . . that has ended, however, for now, and a huge portion of the Arctic has refrozen.

Atmospheric scientists have predicted that the warm Gulf Stream current which warms Great Britain may change its path, putting that area into danger of some cooling.