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Solar flares and orbital changes impact on our climate

A question about solar flares and changing Earth's orbit and what role they might play in climate change from a congressman during a House committee meeting have prompted confusion.

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CO2 measurements and atmospheric samples taken from ice cores
By
Tony Rice
, NASA Ambassador

During a recent meeting of the House Committee on Natural Resources, Louie Gohmert of Texas asked some questions of US Forest Service Associate Deputy Chief Jennifer Eberlien that both raised eyebrows and ridicule across social media.

"We know there's been significant solar flare activity. And so, is there anything that the National Forest Service or BLM (Bureau of Land Management) can do to change the course of the moon's orbit or the Earth's orbit around the sun? Obviously, that would have profound effects on our climate," the congressman asked Eberlien.

Gohmert explained that his question came from conversations with former NASA Administrator Jim Bridenstine where he learned "the Moon's orbit is changing slightly and so is the Earth's orbit around the Sun".

Feasibility of altering solar activity or the orbits of the Earth or Moon aside, these topics come up a lot in climate change discussion.

Changes from these factors do impact our climate but on a scale measured in hundreds of thousands of years, and do so very gradually.

The unprecedented warming trend over the past 100 years cannot be attributed to those natural changes in Earth's path around the Sun or the changes in solar activity. The trend's beginnings also aligns with unprecedented increases in carbon dioxide in our atmosphere.

This graph, based on the comparison of atmospheric samples contained in ice cores and more recent direct measurements, provides evidence that atmospheric CO2 has increased since the Industrial Revolution. (Credit: Luthi, D., et al.. 2008; Etheridge, D.M., et al. 2010; Vostok ice core data/J.R. Petit et al.; NOAA Mauna Loa CO2 record, climate.nasa.gov)

Changes in Earth and Lunar orbits

Serbian scientist Milutin Milankovitch described long-term changes in Earth's motion around the Sun a century ago.

This includes in the tilt that produces the seasons (obliquity), the shape of the orbit from nearly circular to more elliptical (eccentricity), and a wobble in the way that axis is pointed (precession). These cycles affect the amount of sunlight and therefore, energy, that Earth absorbs from the Sun. But these things change over tens of thousands of years,

Milankovitch cycles, or changes how Earth moves through the solar system. (Credit: NASA/JPL)
The Milankovitch cycles provide a good way of understanding long-term changes in Earth’s climate, such as the beginning and end of Ice Ages throughout Earth’s history. But they can't describe climate change over the past 2.5 million years or so.

These changes in Earth's orbit cannot account for rapidly warming temperatures during the last century.

Solar Flares

Solar activity does vary over an approximately 11-year cycle when the Sun's magnetic field flips and calmer conditions give way to increasingly stormy behavior. Those storms can produce solar flares and coronal mass ejections that send increased energy toward Earth.

Comparison of global surface temperature changes (red line) and the Sun's energy that Earth receives (yellow line) in watts (units of energy) per square meter since 1880. The lighter/thinner lines show the yearly levels while the heavier/thicker lines show the 11-year average trends. Eleven-year averages are used to reduce the year-to-year natural noise in the data, making the underlying trends more obvious. (source: Climate.NASA.gov)

However, measurements of the Sun's energy output over the past 40 years show a fluxuation of less than 0.1% playing a very small role in Earth’s climate.

Over the last decade, solar activity waned (as expected) though global temperatures continue to rise.

Courtesy Climate Central

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